Pontifications: Recertification flights for Boeing 737 MAX appear close

By Scott Hamilton

June 29, 2020, © Leeham News: Boeing may be set to begin recertification flights of the 737 MAX as early as today, The Seattle Times reported last week.

Testing will take three days, if all goes well. But Boeing still has a lot of work to do to fully satisfy regulators.

According to The Times, Transport Canada and Europe’s EASA require additional modifications to enhance safety on the MAX. The additional changes may not be required for certification but must be done within a year, the paper reports. The MAX 10 must have the changes before it is certified.

Controversial return to service

Returning the MAX to the air remains controversial. Many, especially the families of those killed in two crashes in 2018 and 2019, believe the plane should be grounded. But changes required after painstaking investigations and reviews by EASA and Transport Canada, essentially double checking the Federal Aviation Administration, should result in fixing all the problems that were found. Some were directly related to the accidents and others were discovered in the course of the safety reviews.

Still, some surveys conducted before the COVID-19 crisis indicated as much as 40% of those surveyed won’t fly the MAX for months to come. These passengers want to see the airplane operate safely.

The MAX isn’t the first airplane tainted by safety issues and fatal crashes. It most likely won’t be the last.

Airbus A320

Safety questions arose over the Airbus A320 after one crashed during an air show demonstration. The model was new; the type entered service only two months before. The A320 was the first airliner that had flight envelope protection designed into the advanced, computerized system. Pilots were skeptical to begin with. After the crash, suspicion that the system trapped the pilots arose.

The investigation concluded pilots were to blame for the accident. In future years, other A320s crashed and pilots sometimes pointed to doubts over the systems again.

The A320, of course, went on to a highly successful sales history. Nearly 16,000 have been sold.


The 737 had a previous black eye that was overcome.

Two crashes and possibly a third were attributed to a malfunctioning rudder power control unit. Solving these proved a mystery until an East Wind 737 experienced a hard over rudder condition at an altitude high enough to allow recovery. The PCU had a design flaw and Boeing’s rudder design didn’t have back-up to prevent this single source of failure. A redesign fixed the issue.

Boeing 787

The development and production history of the 787 already hurt its image. Billions of dollars in cost overruns, 3 ½ years of delays and an in-flight fire on a test flight cast dark shadows over the airplane. But when it finally entered service in October 2011, it seemed most of the problems were behind it.

Then, in January 2013, a lithium ion battery caught fire on a Japan Air Lines 787 parked in Boston. Nobody was hurt, and the fire was thought likely to be a one-off event.

Two weeks later, an ANA on take-off experienced another battery event. No fire broke out, but the battery smoked. The FAA grounded the 787 for three months, until a containment system was designed.

There was some passenger avoidance for a period of time, but the 787 today is considered a highly successful airplane with a solid reputation.

McDonnell Douglas DC-10

The DC-10 was plagued with design defects. By themselves, none caused an accident—other circumstances combined to bring down airplanes. But the DC-10 was grounded in 1979 after an engine fell off an American Airlines flight on take-off from O’Hare Airport. In the end, this accident was traced to an ill-advised engine/pylon removal procedure, approved by McDonnell Douglas and the FAA, which turned out to crack a part that finally failed under stress of take-off power.

The engine flipped up and over the wing, smashing hydraulic lines in the leading edge. Fluid leaked out, allowing the left wing slats to retract. The wing stalled. The pilots followed the operating manual to the letter but didn’t know the engine left the airplane and the slats retracted. The airplane flipped over and crashed into a trailer park.

Stoppers were added to the hydraulic lines in the wing to prevent this leakage from happening again. But it did in 1986, when the No. 2 engine failed and a disk blew apart. Fragments severed the hydraulic lines in the horizontal stabilizer, allowing fluid to drain from all lines. Controls didn’t work and only through brilliant aviating did United Airlines Flight 232 make it to Sioux City (IA). In a spectacular, filmed crash landing, 111 were killed—but more than 180 people survived.

A poorly designed cargo door latching mechanism caused the crash of a Turkish Airlines DC-10, killing all aboard. Previously, an American DC-10 avoided a similar crash by skilled aviating.

The reputation of the DC-10 never fully recovered. But the plane went on to serve the industry reliably until it was retired due to aging and economic issues.

Other Airplanes

There are several other examples of planes that had reputational hits to them. The Boeing 727 had a string of fatal accidents, all ultimately attributed to pilot error. But at the time, the reputation was hurt. The 727 went on to be a successful and highly regarded airplane.

The Lockheed Electra prop-jet wasn’t as lucky. After two crashes six months apart in which a wing separated in flight, traced to a design flaw, the plane’s reputation didn’t recover.

The Douglas DC-6 and Lockheed Constellation were grounded after fatal crashes due to design flaws. Each went on to restored reputations and solid careers. The Martin 202 also was grounded after a fatal crash and a design defect. Its reputation didn’t recover.

Back to the MAX

The point is, the MAX potentially can come back and rebuild its reputation. But it’s not a sure thing. For months, the slightest incident is going to garner headlines as a “blow to MAX,” or something similar. These will be unfair.

If there is another crash, it won’t matter to the skeptics, critics or ill-informed headline writers if the MAX was zapped by a ray gun from outer space. Someone, somewhere, somehow will tie the crash to MCAS.

Only time will tell if MAX’s reputation—and Boeing’s—can be restored to good standing.


271 Comments on “Pontifications: Recertification flights for Boeing 737 MAX appear close

  1. Some good news for Boeing at last.

    I read the article by Dominic Gates at https://www.seattletimes.com/business/boeing-aerospace/foreign-regulators-demand-substantial-new-changes-to-boeing-737-max-flight-controls/

    There’s a quote I don’t understand…

    “For Airbus and EASA, three Angle of Attack sensors is just what you do,” said the person. “For Boeing and the FAA, it’s not necessary, because in addition to the two Angle of Attack sensors, you have that physical connection with the aircraft.”

    I think they miss the point of three AOA sensors, with two, if they disagree, how do you know which one is giving you accurate information ?

    The point of three AOA sensors, is you should have two which agree, indicating that the third is unreliable. It’s not “just what you do”, there’s a very good reason, and it’s not because Airbus is FBW, and the MAX is not.

    I don’t see how having a “physical connection with the aircraft” is going to help the pilots decide which of the two sensors is unreliable. Have I missed something ?

    So as I understand it, on the MAX, if the two sensors don’t agree, MCAS won’t activate, OK that’s fine, but if MCAS is necessary, what do you do if the sensors don’t agree ? Divert to your closest alternate, and land ?

    There’s talk of adding Synthetic Airspeed, which appears to be complex, and expensive. Surely fitting a third AOA sensor would be simpler, quicker, and less costly ?

    • Jakdak, the MAX as designed has a third set of basic reference instruments that do not depend on AoA sensors. So the pilot has an alternative in the event of AoA sensor failure.

      Also with the changes in the MAX AoA display options, the pilots are alerted to a disagree condition and can view the individual sensors. So they would be aware of the exact nature of the failure. This all reflects Boeing’s philosophy of pilots having ultimate authority.

      The point being made by EASA, is that the reference instruments have no value to the flight computers, as there is no interface to them. So the computers are disabled by an AoA disagree, even if the pilot is not. They want the computers to have the third reference as well.

      The third A0A sensor could be physical or synthetic. Physical sensors are connected to ADIRU’s which reduce all the sensor inputs to a digital form for consumption by the flight computers. Thus this likely means adding an ADIRU as well. If you are going to do that, then it may make sense to use synthetic ADIRU, which uses telemetry rather than physical sensors. That adds capability to the aircraft for perhaps somewhat greater cost, and you don’t need to penetrate the hull with new sensors.

      • Rob, I assume any third set of reference instruments, are only good for the pilot to incorporate into his scan, and not involved into the MCAS software sensing programs? So, if/when MCAS fires off from the inputs of the AOA sensors, will the pilot know via a light or some other indication that MCAS has taken control, and then have to cross check to see if MCAS is correct or not, and then, since there is no OFF switch, the pilot will have to decide if he’s in a valid high AOA situation or not, and then take appropriate action, in seconds, to keep the elevator moving or not? We’ve still got MCAS-in-command, rather than Pilot-in-command. Both pilots (the real ones), then have to monitor and fight with MCAS as needed. At least with an auto-pilot runaway, the overpowering of the auto-pilot is natural controls forced hard. To overpower MCAS, the pilot still has the only option of switching off the elevator motor? In the KC-46 design, didn’t / don’t they have a 3rd sensor (some gyro?) built into the KC-46 MCAS version?

        • Richard, the authority and persistence of MCAS have been reduced, so I don’t believe it’s accurate to say that MCAS takes control away from the pilot. It was never intended to do that, and the flaws that permitted that have been addressed.

          As things stand now, MCAS cannot command the stabilizer to an extent that overpowers the elevator. The pilot will have increased forces on the column, but not enough to prevent level flight, even in opposition to MCAS.

          Additionally, pilots now will be specifically trained on how to handle an MCAS malfunction, and will practice it in an accurate simulator.

          As to whether there will be an indicator that MCAS is active, I don’t know. There was talk of that but not sure if it has been implemented.

          As to the secondary safeguard that was removed from MCAS, I don’t know whether it has been restored, but I suspect not. Similarly I don’t believe the column-back cutout switch function has been restored for MCAS.

          The KC-46 and 767 tankers have a different implementation that is more embedded as a native function in the flight controls. It appears that little of that was carried over to the MAX, where MCAS was more of a bolt-on to the speed trim system, which also is unique to the 737.

          AFAIK, the pilot methods to disable MCAS are unchanged. Autopilot engaged, flaps extended, electric trim buttons, electric trim shutoff switch, and manual trim wheel grab & hold.

          With EASA requiring the third AoA sensor, Boeing will have to add code to allow one more step (comparison of three sensors) to the decision to deactivate MCAS, in the case of A0A sensor failure.

          • Rob, Any update on the reset parameters after activation of MCAS? Can it fire repeatedly every few seconds or only a one time shot, until? Thanks, Richard

          • Richard, MCAS can only fire once for each excursion of AoA activation value. To reset the trigger, the AoA value must fall back below the deactivation threshold.

            So the options would be that the pilot responds and lowers the nose, or decides to hold the nose high for an extended period.

            It’s not clear if MCAS will continue to adjust the stabilizer to account for changes in AoA or airspeed while active. My guess is yes but I don’t know.

          • From what I see its a one shot deal, but they have not said what resets the counter.

            My take is that if it resets, then it also re-arms.

            But its been neutral in how much it can move the tail and how long it can run doing so.

            If AOA disagree is present its locked out.

            No its not a return to base. The aircraft bizarre enough flies just fine without it.

            BY putting it in it made it less safe rather than more safe for a miner handling issue at stall that I have yet to fine a reference that anyone has acualy stalled a 737 in service.

          • Actually the 737MAX flies without MCAS no issue, MCAS has a proven lethality to it.

            Its a case of adhering to regs is what created a ripple affect of a horrific design change and deaths.

            If a pilot can’t handle a stall then they are not a pilot. Having stalled a lot of times, you frankly could care less about smoothing, you need to stop the stall.

          • Bizarre that they had this resolved in other aircraft and choose a whole new and lethal approach in MAX.

          • TransWorld, regarding anyone stalling the 737, look up the Turkish accident at AMS.

          • “”Actually the 737MAX flies without MCAS no issue””

            It depends on how turbulent the conditions are. That’s why there are regulations for a linear flight behaviour.
            The MAX doesn’t have a linear behaviour, that’s why Boeing put MCAS in and self-certified it.
            Real regulators won’t certify the MAX.
            This week is all about the FAA, if they want to be a real regulator or a joke.

          • Leon:

            I will disagree as has Bjorn.

            I won’t disagree for a second that the FAA as a regulatory has sever issue and and alwyas has., Its an ugly aspect of how the US Aviation system is put together.

            However, as their political butts are on the line they will be doing this one right.

            The next one I don’t have any confidence in unless the system is reformed. We might get that next year.

          • The only folks that have flown a 737-MAX without MCAS active, in an actual aircraft are Boeing test pilots? Am I right? Turning off motor control to the elevator’s still leaves MCAS active, but, unable to move the elevator. There is no actual “OFF” switch for MCAS. Unless you were able to get to the AOA sensor wires and short them, there is no method, or circuit breaker to turn off MCAS? It’s built into the Speed Trim System of the AutoPilot? But, only actively armed when the AutoPilot is OFF? Would pulling an AutoPilot circuit breaker effectively turn MCAS OFF?

          • I’m not a pilot, but someone mentioned a way to bridge MCAS before.
            I think ET302 tried to use 1 degree flaps but it didn’t work or STS set in, but it should be possible to set MCAS off, otherwise EASA wouldn’t want to try it.

        • I read that the tanker has triplex FCCs or such, being a 767.

          And a mild MCAS-like function.

          Properly designed, deliberately so according to UASAF/Boeing.

      • Uh, Rob, I don’t see the standby flight instrucments as a substitute for AOA vanes, they just provide attitude, airspeed, altitude, and perhaps navigation information. The standby is a Display, not a Sensor.

        A common procedure to keep flying is to hold thrust and airspeed. There’s another procedure that I forget to cover unreliable airspeed such as from nose radome departing the airplane, perhaps hold thrust and pitch attitude. (As AOA is not normally displayed, it may now be in the MAX.) The crew then has to manage the rest of the flight. (Decades ago a 707’s airspeed became unreliable when pitot-static equipment froze from moist air pushed high by winds, crew used the doppler navigation sensor for speed until the problem cleared, the doppler system measures ground speed along track not along heading, wind is a difference between doppler speed and pneumatic airspeeed, so is approximate.

        And ‘telemetry’ won’t help determine AOA, that’s simply a radio link of data. ACARS and CPDL are versions used in regular service, flight test airplanes will have some data transferred by ‘telemetry’, space vehicles too. Since waaay back.

        More likely ‘synthetic AOA’ is calculated from parameters like wing characteristics (which vary with flap extension so that sensor is used), air speed, vertical speed, and pitch attitude. Much less costly than installing and wiring a third AOA vane, and gives a benefit of diversity. “It’s just software.” :-o)

        • Keith:

          The standby instruments are a stand alone system that does not have AOA.

          They have their own pitot, their own static port. Its a smallish combined unit (all data displayed on a small format) between the pilots.

          Sadly they are in a very poor location. Backup ref was once in the instrument scan with the other instruments and you could easily can the gauge that was off and pick up and use the confirmed good one.

          I don’t like it and how its treated.

          Better would be each pilot has one in an easy to see location in front of him and or the pilot can pop it up on the display in front of him in larger format.

        • Keith, the issue at hand was that the pilot’s judgement along with the reference instruments can mange the aircraft without MCAS or AoA. That’s what was meant by the physical connection to the aircraft.

          The flight computers need AoA to refine their sense and estimation of the aircraft behavior in flight.

          Telemetry can include GPS and other information sources from outside the aircraft. Those can be part of synthetic air data.

          • I am in principle wary of information from outside the aircraft for ‘synthetic AOA’, that adds another dependency.

            Note that GPS signals can provide flight path over some time as they are in effect a position source when correctly processed, _but are earth-referenced_ not air-referenced as needed to estimate AOA. Air data sensing is air-referenced. Keep in mind the ADIRUs have air data and attitude information, separate from the FCCs. (On the 737MAX apparently they process AOA data as vane angle needs adjustment for at least some uses, and air data may need correction for AOA. Thus ADIRUs are in a position to check on validity of vane angle, I expect. Certainly complex, which I _guess_ may be part of the too-many-warnings problem.)

            (As for sensors, TransWorld does point to air data sensor in or dedicated to the standby display.)

          • Rob, and Keith,

            A good discussion. A well designed flight system does not lead to conflicting or contradictory alerts, warnings, or indications.

            A well designed system fails in as safe a way as possible, one failure should not trigger a cascade of issues.

            Flight displays should perhaps use a model similar to:
            Green lights/diagrams/figures indicating all good.
            Amber, things that need to be looked at pretty sharply.
            Red, immediate attention, specifically in the order shown.

            Display normally shows all green, as a situation develops green is still visible, but fades down, as amber fades up. When a Red condition occurs, both green, and amber fade out completely, first priority item in red fades up significantly higher than other red items, pilots deal with issues in turn.

            An AOA failure would be indicated, but the system would continue to function using ‘last known good’ value if the input was massively out of range almost instantaneously e.g. AOA sensor hit by a bird.

            I’m really interested in the differences, and design philosophy between the SpaceX Dragon capsule flight controls (touch screen very few buttons), and the Starliner flight controls.



            A note on the AF296 crash that Scott mentioned up top.
            There may have been issues with the FBW implementation, it was the first passenger flight of the A320, but there were a number of factors.

            The display was supposed to be 100 feet AGL, but ended up being 30 feet. It was supposed to be along runway 02 in one direction, and then back in the opposite direction.

            The spectators were moved to runway 34 right at the last minute, the pilots, unfamiliar with Habsheim aerodrome were not aware of a forest at the end of runway 34R, in any case they had planned to fly over 02 not 34R.

            So no advance recce flight, spectators moved at the last minute, deviation of flight plan, subconscious pressure on the pilots to perform the display, and poor understanding of ‘alpha protection’.

            We learn from this what the US Military term the 6Ps.

            I remember seeing the footage of the crash on the news at the time, and I was surprised that only 3 people died out of the total 136 on board.

    • Of course 3 is better than 2. And by the way 4 would be better than 3, because it adds redundancy. On the other side more than 10000 B737 Original, Classic and NG were build with just 2 AOA sensors. And it seems till the Max-accidents there was no problem with just 2 AOA sensors.

      The underlying problem with the Lionair and Ethiopian crashes was not “just 2 AOA” sensors. It was bad code and bad communication from Boeing rooted in a policy “profits over safety”. If the Max had 3 AOA sensors then the planes from Lionair and Ethiopian would still have crashed, because MCAS used only the data from one AOA sensor. And then it doesn’t matter if you have redundancy with 1, 2 or 3 more AOA sensors.

      • Ironically until the fighter mafia got into the game, AOA was not on jet aircraft and they did fine without it.

        Huge numbers of former fighter pilots (and a few random Herc, C-141 and C5 pilots) came into the industry.

        If you were using AOA for a climb, its pretty sloppy as they can be off from each other (5 deg now) and be fine. Hmmm.

        • Hercs et al are quite different beasts from fighter planes, they are transport airplanes – big, slow.

          Working with its performance I viewed the Herc as quite like the 727C and 737C, just an easier to load cargo compartment, no pax, and lower pressure tires. (About the same weight, and speed at modest altitudes – as fast as the 737C at 350 knots indicated until Mach effects took over then the jet went faster. Significant time savings of 727C over L188 Electra on flights into the High Arctic.) Herc and Electra had advantage of quicker engine response to get out of trouble on approach, PW installed HUD on the 737C and 727C plus the Herc.

          (Ironically, Continental’s Air Micronesia crashed an ex-PW 727C that HUD would have prevented, black-hole approach to sloping runway, but they’d removed the HUD.)

          I never spent enough time studying the Herc to remember if it had AOA display, it did have a vertical acceleration display (‘g-meter’), mostly commercial instrumentation on the ones I worked on. I focused on HUD and some other things, good stuff. And High Range Radio Altimeter for navigators – that’s old 😉

      • The basic 737 was instrumentation wise a “bifurcated” design. clean. two seats with two sets of instruments indicating state. pilots to decide on sensor saneness.
        Sensor errors had no direct “push through” being filtered by the pilots.
        Various warts where added over time that broke this paradigm ( like the radar altimeter integration that is asymmetric. the AMS TK crash put this on the table.)

        Speed trim and later stall protection MCAS broke this and added direct “push through” from sensor to aero surfaces
        without adequate fault protection breaking the basic design concept ( “independent lobes”) from the 60ties.

        Today’s 737 is a Frankenstein Onion.

        • Uwe, the paradigm was expanded rather than broken. To imply you cannot add automation under the FBP system, or unless it’s full FBW, is not really valid.

          Note that autopilot also does “push-through”. Pilots can still decide on the use of automation and override it. That is true of speed trim, auto-throttle, autopilot, and MCAS.

          It might be more accurate to say that MCAS and speed trim are different in the sense that the default state is on, with the pilot needing to intervene to turn them off if required.

          Speed trim has been an incredibly safe system, as noted by Peter Lemme in his analysis. MCAS was not safe due to numerous flaws, but should be now with the current improvements.

          • always nice to read what Boeing wants us to think 🙂

          • Thank you. Always nice to establish the truth and refute what the anti-Boeing crowd wants us to think.

            At some point you may realize that the agenda of that crowd is to do as much damage as possible, to disrupt and tear down the company if they can. Which is pretty pathetic.

            None of you could reproduce what Boeing has done and achieved, regardless of the many acknowledged problems they have. It’s far easier to destroy than to create.

            I try to focus on solutions to the problems, which create as much benefit as possible. This is an important philosophical difference, that is always lost on those who seek to destroy. They will always feel justified in the destruction, as no doubt you and others here do.

            So you use derisive language like Frankenstein, flying coffin, deathtrap, etc, which have no factual basis. But that language identifies the true intent. There is no need or role for derision or ridicule in factual criticism.

          • “”None of you could reproduce what Boeing has done and achieved””

            Rob means the same Muilenburg said “We own safety”.

            Rob means fighting against the victim families for every penny.

            Rob means Boeing’s first rule: “Blame the pilots”.

          • I think Rob’s Boeing means the long serving engineers and other employees not the ‘other Boeing’ senior managers and top executives.

          • Rob, as there is no Reply button to your reply to Uwe I post here.

            “Similarly the “wait for Rob” and “Boeing employee” remarks are an attempt to discredit the response. It’s sad in a way, because the use of those methods shows high intelligence, but also highly misdirected.”

            Indeed, thankyou.

            The problem your protagonists have is corrupted values, their tactics show shallowness (inability to think well). Comonly from a collectivist mindset such as Marxism, in contrast to objectivity which looks at reality and judges based on human values. As philosopher John Ridpath explained, they’ll get angry because they have used their method of knowledge – emotions – for so long they cannot straighten out, they just double-down. (And there are Euro-basher conspiracy theorists about.)

            Broad-brush claims are revealing. They remind me of the old saying “Throwing the baby out with the bath water.” 😉

            And people like Leon who think they are experts, reminds me of the remark someone made in a forum when he got tired of fem-bashing after a USN pilot crashed her airplane approaching an aircraft carrier: “I didn’t know so man people could fit in the flight deck of an F-14.” And “A little knowledge can be dangerous.”, IMO Leon has physics backward sometimes.

          • Thanks for mentioning me, Keith.
            I never claimed to be an expert.
            But I’m not so stupid to believe Bjorn when he said that MCAS is safe now.
            What is it worth when the so called experts at Boeing and the FAA let people die because of $$$ ?
            Boeing digged the hole they are in themsleves. This is EPIC.
            I’m sure all victims are on my side.

          • Keith, I do judge Rob to be a rather accomplished rhetoric. ( He also is an engineering poser.)

            But it’s application is better limited to religion.

            At the core of the Boeing’s woes is exactly what Rob works rather well : certification conformance brinkmanship massively aided by rhetoric curlicues.

            In the long run engineering does not work on rhetoric niceties. It appears to work for a while until all over a long time accrued (savety, other) margins are consumed. :: MAX .

    • In order to have physical connection with the aircraft in the 737-MAX case, they need to put the cutout switch back in the yoke control (which negates the MCAS system’s role entirely). Since I still don’t see a true “OFF” switch for MCAS, then the only thing Boeing has done, is to add in a 2nd AOA sensor to
      turn “OFF’ MCAS. They still don’t allow the Pilot-in-command (or rather MCAS-in-command, in the case of the 737-MAX), to be allowed to turn MCAS off. This to me necessitates a true fly-by-wire certification for the MCAS software and electronics.

      • I am having to try to review what all the MCAC 2.0 fixes were (vs the other changes that are irrelevant to the MCAS 1.0 crashes )

        While they only say it fires once per incident. I assume that means if the AOA is back to normal and reverts it fire again (assuming there is not an AOA disagree)

        Still have not seen the line by line fix and if the Yoke cutout is back or not.

        One comment was the trim switch is active but it always was active.

        With reset auto on MCAS 1.0 you had to constantly trim.

        And is that an issue with the Trim motor.

        Add in why they took one trim motor our of the NG and carried onto MAX and how that affected things.

        • Indeed, comprehensive knowledge of the modification package is needed to have a meaningful opinion.

          Some bashers don’t even know much about how airplanes work and are flown. They are collectivists – ‘Boeing can do nothing right’ (don’t see many in this subject saying ‘Boeing can do nothing wrong’ 😉)

          Beware there are multiple switches related to stab trim, including:
          – The one on each control column you are referring to.
          – The one on each control column on a horn of the control wheel which is on top of the column, the ‘pickle switches’ is one name, still there and used routinely by crew.
          – Perhaps another on the main panel to return a function that a fault monitor may have disabled.

    • Jak:

      You need to go back to the stupidty of the AOA and MCAS to get the real core issues.

      The assumption was AOA disagreement was miner and a nose down nudge solved it.

      What they blitlely glossed over, was a damaged AOA (or a failed one) that never changed its value. That is not uncommon due to ramp hit, bird strike and amazingly not doing your ground checks after a repair AND after replacing one.

      So, when you had an AOA feeding steady bad data, MCAS never stopped dumping the nose as you would alwyas have the condition.

      When I read that they used a single input to trigger a dive, it was they are out of their (insert nasty bad word here) out of their minds.

      Now you need both AOA to agree (within 5 degrees) or on disagree, its locked out.

      The amount of authority is hugely reduced from the spiral up authority they implemented on MCAS 1.0.

      I am less sure if they put the cutout switch back into the column but I think so (that bizarrely was removed on MCAS 1.0 which contradict all previous 737 ops training and not mentioned to the crews)

      Maybe they should have a big RED fake flaps down button that says PUSH HERE in CASE OF MCAS EVER RAISES ITS HEAD.

    • The MCAS was introduced to bypass trainings for NG pilots. With MCAS only 1 hour of training on iPad was needed to transition from NG to the MAX. That’s how Boeing was selling its plane. No training needed. Just jump in and fly.
      I think now the pilots are required to go through a training? I think. In this case why do we need more AOA sensors than what we have on the NG?

      • Actually the reason for MCAS was to meet regulations for control column forces. Since the NG is also compliant with those same regulations, it’s valid to say that the MAX handles like the NG.

        Training is required because random pilot testing in December showed too much variation in pilot responses. That shifted the landscape, as it became obvious that the argument to not require training was not supported by pilot performance.

        The MAX flight control software is now completely different than the NG. It offers the opportunity to support a third sensor and use it to resolve AoA disagree situations from the original two sensors. Thus EASA made it a condition for certification, but on the MAX only.

        • Rob:

          Training is required because Boeing changed the whole system and did not tell anyone they had done so.

          Control column cutout no longer worked. That is huge and also a lie put to the Boeing so called philosophy of a pilot can alwyas override the automation.

          And lets not forget that Boeing also changed the manual trim ops in the Simulators so it no longer worked the way it does int he real world.

    • ‘JakDak’
      With fly-by-wire more redundancy is needed, hence triplex flight computers.

      EASA explains that after distracting by misleadingly praising Airbus and the A320. (Yah, sure, like the recessed installation of the A320’s AOA vanes that facilitated freezing of them from rotating when wash water was not blown off before takeoff – a common-cause failure mode.)

      The point is that the 737 can be flown manually as controls are connected to surfaces with cables, thus does not need triplex redundancy. Simple.

      A disagreement between AOA sensors will now disable MCAS, I understand, but not stall warning. What’s different about the MAX from earlier 737s? Is there not a circuit breaker feeding power to each shaker motor?

      BTW, there are two key differences with MCAS type function between 737MAX and KC-46 tanker:
      – On the tanker the function was deliberately designed as mild in action, for safety.
      – The tanker wants it to help crew handle the large rapid shifts of CofG from transferring fuel to receiving aircraft and within tanks onboard.
      I’ve sympathy for the TC engineer who questioned the need on the MAX compared to the complexity it added, but there is a regulation about pitch control forces that Boeing first encountered on the 767. (Those designers chose to add a few VGs to the wings rather than a triplex correction system.)

      • Keith,

        Why I made the original comment, was more a point about two information references, and why three makes more sense.

        I understand that the MAX can be flown manually (as can the Airbus aircraft in a way), what I was trying to understand is, if you have two AOA sensors, and one of them malfunctions, how does a pilot decide which one is correct, and which one is not ?

        The method of controlling the aircraft is irrelevant, what I was interested in is how does the pilot get the correct information to instruct the aircraft what to do.

        The pilot can modify pitch, yaw, and roll mechanically, but that doesn’t tell him while flying on instruments what his situation / attitude is, you can’t fly ‘by the seat of your pants’ when you’re flying an aircraft at night in the middle of a cloud.

        That’s why I found the statement “For Boeing and the FAA, it’s not necessary, because in addition to the two Angle of Attack sensors, you have that physical connection with the aircraft.” odd.

        Rob has explained that there are alternate instruments (such as the standby airspeed indicator) that a pilot can use to understand the attitude, airspeed etc. It has nothing to do with the physical connection with the aircraft.

        I do wonder with the changes made to the system, when the two AOA sensors don’t match, will this result in an “Unreliable Airspeed Indication” as AOA disagree will disable MCAS, but not stall warning ?

        As I am very interested in user interface, and human factors, I agree the Airbus system is not perfect. I’d like to see active, linked side sticks, and back driven throttles. These are useful visual, and subliminal clues that would enhance aircraft safety.

        A simple solution for Airbus would be to add Haptic Feedback to the side sticks if they were moved in opposition to each other. As we don’t have a need for a ‘stick shaker’ on Airbus aircraft, we could re-purpose this instead of active side sticks. We have this sort of technology in our phones, so it’s small, reliable, and cheap, and would only need a small motor in the side sticks, and minor software modification to achieve.

        • Hello JakDak,

          Re: “The pilot can modify pitch, yaw, and roll mechanically, but that doesn’t tell him while flying on instruments what his situation / attitude is, you can’t fly ‘by the seat of your pants’ when you’re flying an aircraft at night in the middle of a cloud.”

          The “Control Performance” and “Primary and Supporting” methods of instrument flying that are typically taught to non-military pilots use the attitude indicator or artificial horizon (gyro or laser gyro instruments) as the primary attitude indicator, they do not depend on an angle of attack indicator. To initiate a climb, you do not set a particular angle of attack, but rather adjust power and pitch and cross check with the altimeter and vertical speed indicator. Note that pitch is not the same as angle of attack. They tend to be similar in an aircraft maneuvering slowly and gradually but can be very different in aerobatic and sudden sharp maneuvers, which is why military fighter pilots are trained to make more use of angle of attack than commercial transport pilots. An aircraft in a nose down spin has high nose down pitch, but the wing is angled up relative to the direction of travel. The power instruments mentioned in the excerpt from the first link below are those that would be present in a piston powered aircraft.

          “Primary and Supporting Method:
          For any maneuver of flight condition, the pitch, bank, and power control requirements are most clearly indicated by certain key instruments.

          These are your primary instruments while those that back up these indications will be supporting.

          Pitch Instruments:
          Attitude indicator
          Airspeed Indicator
          Vertical Speed Indicator

          Bank Instruments:
          Attitude Indicator
          Heading Indicator
          Magnetic Compass
          Turn Coordinator

          Power Instruments:
          Airspeed Indicator
          Engine Instruments
          Manifold Pressure
          Engine Pressure Radio (EPR)

          The above quote is an excerpt from the following link.


          The excerpt below is from Chapter 6 of the FAA instrument flying handbook.

          “Pitch Control
          Pitch control is controlling the rotation of the aircraft
          about the lateral axis by movement of the elevators.
          After interpreting the pitch attitude from the proper flight
          instruments, exert control pressures to effect the desired pitch
          attitude with reference to the horizon. These instruments
          include the attitude indicator, altimeter, VSI, and airspeed
          indicator. [Figure 6-4] The attitude indicator displays a
          direct indication of the aircraft’s pitch attitude while the other
          pitch attitude control instruments indirectly indicate the pitch
          attitude of the aircraft.”


          • Thanks Robert,

            Like you I have some time in a 152 (I decided not to continue as I could not guarantee to do enough hours every year to satisfy myself that I was safe enough to my own standard.)

            What I was struggling with was the wording of the statement “For Boeing and the FAA, it’s not necessary, because in addition to the two Angle of Attack sensors, you have that physical connection with the aircraft.”

            It’s nothing to do with the physical connection to the aircraft, it’s everything to do with where / how you get information that you can rely on to aviate.

          • Keith,

            The A320 has mechanical backup for both rudder, and pitch trim. Later Airbus aircraft have backup systems that are completely electrical.

            The Airbus system is controlled by ‘laws’; normal law, alternate, direct, and mechanical. As I understand it, mechanical law can be used to fly the aircraft without the involvement of the computers (to all intents, and purposes, manually).

            All protections are obviously off, movement of the rudder pedals produces relative motion of the rudder surface, pitch trim is used to move the elevator etc.

            Yes it is dependent on the electronics, certainly in the A380 which has a dedicated Backup Control Module which uses electrical signals to activate hydraulic actuators.

            I’d love a 320 driver to comment on what it’s like to actually fly a BUS using mechanical law, so yes … the Airbus aircraft can (in a way) be flown manually.

            I’ll have to see if I can find any cockpit videos where the pilots are flying a BUS in mechanical law.

            It wasn’t EASA’s statement about physical connection to the aircraft, in the Seattle Times article, it’s:
            “According to the person familiar with the FAA’s deliberations”

            What was confusing is that it has nothing to do with a physical connection to the aircraft. Fly a C-152 or an A330 with absolutely no visibility, and it doesn’t matter that all control surfaces in the 152 are connected by wire, what you need to know is which way is up, down, airspeed, altitude etc. If you have two instruments, and they disagree, wire connected surfaces don’t help you determines which is correct.

            As Rob explained the pilot would use the standby instrumentation.

            For the two MAX accidents, a loss of AOA sensor seems to have precipitated a confusing situation in the cockpit, instead of just losing AOA data (no great loss in itself), it triggered stick shaker, and potentially unreliable airspeed indications, throw in ground proximity warnings, and overspeed clacker in the case of Ethiopian. MCAS then created another level of problem where all of the above really didn’t help matters.

            There are serious lessons to be learnt here, as there were for AF447.

            My personal view is that adding complexity to an already complex situation is seldom a good idea.

            I wonder if after accepting that pilot training was going to have to be mandatory for return to service of the MAX, it wouldn’t have been better to remove MCAS entirely, and just train properly for those areas of the flight envelope (apparently very rarely encountered) that MCAS was ‘designed’ to deal with.

            I don’t think a ‘cure should be worse than the disease’.

            I don’t think following a dogma such as ‘pitch moment must be linear at all costs’ should lead to a point where common sense doesn’t prevail.

            I’m not interested in blame, or politics. I’m interested in genuinely understanding what actually went on, what we can learn from it, and how we improve things.

            We can’t bring all those people back from the dead, but we can honestly look at the ‘why’, and make sensible changes to prevent future loss of life.

          • Jakdak, very well said. Right on point.

            Only comment would be on the alarms, they were a function of the ADIRU which uses A0A for air data correction. Like the defective radar altimeter in the AMS flight should have done, it flags its own data as unreliable when it senses a problem. That feeds into the alert systems.

            Stick shaker is a warning, so perhaps the reasoning is that stall is serious enough that the warning should occur even if the sensed low airspeed is unreliable. Or perhaps it is a poor design. I don’t know how those choices are made.

            My own reasoning, is that unreliable and shaker on the left, but everything ok on the right, plus the reference instruments and radar altimeter agreeing with the right, means follow the right and not the left.

            However since the aircraft behavior was aligned with the left due to MCAS, it’s understandable they would continue to focus on the left. That gets into human factors and how people respond to complex situations. You naturally focus on what’s wrong rather than what’s correct.

            In the Apollo 13 crisis, Gene Kranz had the insight to ask what was working on the spacecraft, which shifted the focus of the team to using resources, instead of the uncorrectable problem. But that is the benefit of being the observer, as we saw also in the JT043 jump-seat pilot.

            I’ve thought a lot about that, can you design alerting systems so they steer you away from the malfunction and to the working tools and resources, even if that seems counter-intuitive. I’m sure human factors experts could illuminate that issue, and what the criteria might be for making that transition.

            Anyway, again great post!

          • Thanks Rob,

            I agree Human Factors are a very big part of this. Boeing, the FAA, probably most other airframers, and authorities had an expectation of how the pilots would perform. They expected the same level of performance as a fully briefed test pilot. They didn’t actually use a cohort of very average line pilots to confirm their expectations.

            What’s quite shocking is that now when they have run some average pilots through a sim on similar flights to the crashes; despite all the press, despite the level of interest of the pilots, despite being in a way, prepared, and having a mental plan to deal with the issue, a number of the pilots still followed the incorrect check list, or performed tasks in the wrong order. I understand that some even failed to save the flight.

            That really tells you something needs to change. We are relying in automation a great deal more, but we really have to understand, and design in the Human Factors. We also need to challenge our assumptions, and verify our expectations.

            Question everything, follow the data.

        • Explain to me how the A320 can be flown manually as you claim.

          It depends on the electronics.

          The 777 does have a cable back to the elevators or horizontal stabilizers, as a backup of some sort.

          As for EASA’s statement about physical connection to the aircraft, you are extrapolating out of the context which was flight controls not displays to guide piloting.

          • Keith,

            An update to my post above. I did find a reasonable video explaining the A320 flight laws.


            First, a closer approximation of manual flying of the 320 seems to be Direct Law, described, and demonstrated in the video. Pretty much no computer input ‘direct’ control of surfaces through side stick, and rudder pedals. But if electrical / computer failure, then you’d resort to Mechanical Law.

            About 25 minutes into the video, Mechanical Law is briefly explained, and yaw demonstrated with the rudder pedals (roll would be a consequence of yaw in this case).

            The instructor (very, very young) explains that the aircraft is not designed to land in Mechanical Law. I suspect although it’s not designed to land in Mechanical Law, it may be possible. Hopefully some of the lessons from United 232 have been taken into account.

            I’d be interested to find out if the flaps still operate in Mechanical Law.

        • A simple solution for Airbus would be to add Haptic Feedback to the side sticks if they were moved in opposition to each other.

          red Herring.
          Airbus sidestick dual input from both seats causes a “DUAL INPUT” aural warning.

      • “BTW, there are two key differences with MCAS type function between 737MAX and KC-46 tanker:
        – On the tanker the function was deliberately designed as mild in action, for safety.”

        The only really counting difference is that apparently the

        Tanker MCAS gets sanitized AoA data.

        737MAX takes raw data unchecked in the initial design.

        • Actually the two MCAS systems are completely different except in overall purpose of handling augmentation. I’m sure sanity checking of the data is part of the tanker version, and was a glaring omission on the MAX, but by no means is it the only difference.

          The tanker version is far more sophisticated. It protects the pilots from unanticipated trim changes, but backs off as the pilot engages the controls to compensate. It yields to the pilot by definition, as it’s integrated into the flight control system. So there is not really the same behavior.

          • Rob, Teflon is an interesting material.

            to repeat what you ignored:
            “The only really counting difference is that apparently the

            Tanker MCAS gets sanitized AoA data.

            737MAX takes raw data unchecked in the initial design.”

          • Uwe, the point was to explain that the two systems share little in common except the name. One of the original questions we asked was why, if MCAS was derived from the tanker as originally reported, it would be missing such obvious things as sanity checking.

            We now know why, only the concept was really carried over, but the implementation was wholly new and different, which allowed errors to be introduced.

            One of the many process errors, was if the military tanker guys suggested MCAS, they should have been further involved or consulted. The development work could have been taken back to them for an opinion, as they wrote the book and were the most experienced.

            You’re seeing a defense of MCAS & Boeing where none was intended. But it is useful to understand why things happened, even if they were wrong.

        • I read that the tanker has triplex systems and uses them because of the potential safety impact of even its mild MCAS.

          You overlook the aggressiveness of MCAS on the 737MAX that made it difficult for pilots to diagnose and cope.

  2. The fact that the best aviation engineers in the world (or so you would believe) needed more than 1.5 years to fix a “perfectly safe” (as confirmed by Boeing) aircraft tells me enough that there were quite a few things wrong on that plane. Given the enormous financial pressure Boeing had to get this aircraft in the air again, and given the history of “shareholders first” at that company, I do not have much confidence, that the aircraft is as safe as it could be.
    I let a few other test fly this plane, and will certainly avoid it for years to come. Luckily in my corner of the world, there are not that many 737 flying, so it shouldn’t be that much of a problem.

    • With all the time Boeing has spent on the MAX, it should be one of the safest planes in the sky. I would not hesitate to fly on the MAX. The DC-10 had a bad crash and came back to fly safely again.
      I forsee very few people refusing to board the MAX as most passengers are oblivious as to what plane they are flying on.
      Boeing did not rush the changes and upgrades to the MAX as they know their reputation rides heavily on the MAX returning to service.

      • Boeing did not rush the changes as they had FAA and the World AHJ looking at them AND they kept finding other issues.

        Boeing deserves zero credit. Hard working emplyess do, but as with MAX the best employee can’t get around an idiot management culture.

    • The 737 MAX is in a “design coffin corner”.
      No way to step.
      Whatever you change you are stepping on a wide range of assumptions and implicit but submerged dependencies.
      too many layers and those also bend basic paradigms from back when.

      Wait for Rob.

      • This is yet another version of the “inherently flawed” thesis. It hasn’t been supported by the certification & review process, which hasn’t revealed any such deficiencies.

        All designs have constraints and trade-offs created by their defining assumptions. Iterations of the design will inherit those as well. But that doesn’t make them automatically bad designs.

        As with the “push-through” argument, this is a negative conclusion that isn’t reasonably supported by the truth of the basic statement. But it achieves the goal of creating a negative impression.

        As Scott said, these things will always be asserted by some, even with a positive outcome, and it won’t be fair, because fairness is not the goal. So it will always need to be refuted.

        Similarly the “wait for Rob” and “Boeing employee” remarks are an attempt to discredit the response. It’s sad in a way, because the use of those methods shows high intelligence, but also highly misdirected.

        • “”As Scott said, these things will always be asserted by some, even with a positive outcome, and it won’t be fair, because fairness is not the goal.””

          The FAA and Boeing who both cheated and killed many people are now doing certification flights ALONE.

          Fair would be that the MAX won’t be certified in the rest of the world. If the goal is to certify a domestic plane I really don’t care.

  3. Nice summary of previous models with issues.
    Not sure if the MAX properly fits into that line-up because, in the case of the MAX, there is much evidence / allegation of deliberate shortcut-taking / shoddy design in order meet cost and timing targets. In other words, it appears that engineering had to take a back seat to facilitate profit. This aspect has had a particularly nasty effect on the reputation of the MAX (and Boeing itself).
    In the case of the other models listed above, the errors appear to have been pure engineering oversights, without a profit motive.

    • To implement a sane system would have taken more time, keep in mind the need for MCAS was a knee jerk reaction to when Boeing said there was no need.

      Pretty much like a two year old to pick up his toys, Well fine!! And then stuffs them in the closet in a mess rather than acualy put them away. Mammam , mmama, I cleaned them up! Can I have my ice cream now.

      Faked the mission intent and walked away.

      You also ignore the deliberately undercutting of the inspection chain when Boeing worked to and succeed in getting the Boeing inspectors to report to them not the FAA.

      That clearly is a control move for profit so that management can stop a report of an issue so they don’t have to deal with it.

  4. I get the feeling that the most damaging issue regarding the MAX debacle was not so much the flaws, this will happen regardless of what safety protocols take place. Instead what is so damaging is the ingrained disregard for safety that was laid bare in Boeing. A acceptance of second best engineering and corner cutting.

  5. Fingers crossed all goes well for the recertification flights and process and that they do lead to a genuinely safe airliner.

    As for “The MAX isn’t the first airplane tainted by safety issues and fatal crashes. It most likely won’t be the last.” though, if airplane is really more narrowly airliner, I think it is more likely that it will actually be the last Western airliner tainted by safety issues.

    Design capability is way beyond the mid 20th century, there seems to be no paradigm shift in pilot UI (as with A320) in the offing and, most importantly, no remaining Western manufacturer can have experienced or looked at what happened with MAX and concluded this is an acceptable way to do business. It is hugely detrimental to profits, shareholder returns etc. It is a potentially existential risk. It simply won’t be allowed.

    Yes the inclusion of hydrogen and electric will be challenging and elevate potential technological and design risks. But business risk will speak and ensure that they are dealt with.

    Yes, at some point, airliners may become single pilot operated or fully autnomous, but I think this is actualy unlikely any decade soon.

    Small “air taxis” manufactured by emergent manufacturers are another matter. The need for business traction to win market share could lead to problems. A properly fucntioning regulatory environment should deal with this though.

    • Is the MAX the fist aircraft that flew perfectly fine (see note) that was improved such that it became lethal though?

      I still have issues with the Manual Trim part and its lock up in certain flight modes and or motor failure and having to break out the clutch if that is even possible.

      • Still, reports came down showing there was pilot error and flaws in maintenance were cited. No other Max aircraft in other parts of the world was reported to have the same problem. AA,UA and WN had many frames in the air along with MAX 737’s in Europe. No reported issues that I heard.
        News last week about Pakistan airline pilots having bogus licences, wonder if the two that went down had suspect pilots?

        • The accident pilots’ histories were fully investigated in the accident reports (although the ET302 report is not yet final). There was no fakery identified. The pilots were fully qualified but had some weaknesses in their pilot check histories that informed some of their actions on the flights.

          This was mentioned in the report conclusions, but was not highlighted in the recommendations, which mostly focused on Boeing and the FAA for permitting the MCAS flaws to exist.

          We have to be careful not to fall into the either-or trap. The causes of the accidents involved both the MAX and pilot actions. For the first accident, airline & maintenance actions were also involved.

        • Steve,

          The core of the issue is that Boeing put a system in place that put pilots on a position to fail.

          We could have all Sullenburg on the wheel, and cut the flights in the world by 80%. He was not a result of the system, but an outlier.

          So, while lessons include pilots and training, we did not need to kill 347 people to know that. Plenty of non fatals to reveal that fully, including AF447 with an all white western crew.

  6. According to the 6-28-20 Reuters story at the link below, the FAA has reported to the US Congress that all reviews that needed to be done before MAX certification flights could begin have been completed, and that the flights could begin as early as Monday 6-29-20. Below is an excerpt from this story.

    “WASHINGTON (Reuters) – The Federal Aviation Administration (FAA) confirmed Sunday it had approved key certification test flights for the grounded Boeing (BA.N) 737 MAX that could begin as soon Monday.”


    The 6-27-20 Reuters story at the link below reports some additional details of the flight test plans.


  7. The MAX will be safe. It was considered safe before the accidents. Apart from the fixes related to the accidents, which were absolutely major & serious flaws, the other non-accident related changes will also help to enhance safety. Most of the grounding time was invested in improvements unrelated to the accidents.

    But the most significant finding, in my view, is the understanding of how pilots respond to incidents. As we saw in the behavior of the MCAS malfunction pilots, there was wide variation in their reactions. This was confirmed again in the random pilot testing that was done in December. We see it also around the world, in other incidents. We see it in the digests of accident reports, as presented in documentaries.

    You do not have to be a bad or incompetent pilot to make mistakes. It happens to good and experienced pilots as well. The best protections are alertness and training and procedure and understanding of the aircraft and its systems.

    The JATR report made clear that the design standards for pilot responsiveness were derived from test pilot training. An admonition for test pilots to identify an issue within one second, then wait three seconds before response to avoid over-correction, eventually became the infamous four-second response design criteria.

    JATR also wrote that at the introduction of automation, pilots were trained to monitor those systems as they would another pilot, and be prepared to step in if needed. However the extreme reliability of automation has eroded some of that awareness, and introduced some complacency. Pilots are now often surprised if automation fails. They tend to view it as infallible.

    So hopefully that will be changed now, so that pilot training emphasizes understanding of the aircraft, adherence to procedure, and regular practice and maintenance of manual flying skills. Civilian training could incorporate some military-style drilling on handling unexpected events. Also that the training itself should not be viewed as a cost to be avoided, but rather as a benefit, even if it seems redundant.

    I saw an interview with an instructor pilot, where he was concerned about the erosion of his own skills during the COVID crisis. His view was that, just like aircraft that are most reliable when flying regularly, pilots are also most reliable when their skills are in constant use. He said he has slowed down his cockpit procedures and those he flies with, due to the risk of error being higher until skills are sharpened again.

    I think the analogy with the aircraft itself was very apt. We check airplanes routinely because we know that failures are possible. We should give pilots similar means for self-checks and self-awareness. For example the aircraft could issue a report to pilots after every flight, highlighting strengths and weaknesses.

    These would be good approaches and I hope they will be adopted more widely around the world, with some of the forward-looking initiatives of the FAA and other world aviation agencies.

    • I think the JATR report is loud & clear on what went wrong & should be changed. They put it together in 12 recommendations. I won’t sum them up, read yourself:


      Hand picking / selecting fragments and working public perceptions worked for years, for the fully supported #1 US exporter & employer. But now carefully pointing at the pilots again, would make EASA, TCCA and CAAC hesitant & suspicious again. They were part of the JATR & want to be taken seriously, not side-lined the old way.

      I hope Boeing isn’t trying to negotiate, delay, pressure, self regulate themselves out of this, but take the JATR recommendation completely seriously. Otherwise they might be headed in the direction of a wall. With or without test flights.

      • It’s fundamentally wrong to focus either entirely on pilots or entirely on manufacturers as the source of problems.

        Astute observers are pointing to a more holistic approach, that looks at the combined transport system of man, machine, and interface. In that system, human failures are responsible for ALL incidents, whether fault is found in aircraft or pilot.

        But since pilots are exclusively human, they clearly dominate the cause matrix. No one should be surprised by that, or use it to excuse the other human failures that result in aircraft faults.

        The goal is to look at the system across the board to identify weaknesses, then address and improve them, without regard as to the source. Boeing has just done that at enormous cost, both reputationally and economically. We all hope they have learned the clear lesson. I would love to see that same effort being made with regard to pilot training and improvement.

        How could that possibly hurt anything? Are we afraid of pilots being over-trained? Over-competent?

        No, we are afraid that attention directed at pilots, will somehow distract from the attention being directed at manufacturers. That is silly and ill-considered. One does not detract from the other. But it’s part of the game we play.

        It doesn’t matter what side of this game you’re on. The only way to win, is not to play. You look at all issues and all causes, and then you work on them all. To do otherwise is folly, and will almost certainly result in further loss of life.

        • The reality is tht there are two huge complely differtn aspect to the two parts of how an aircrar operates.

          MFG: Boeing in this case has done its utmost to undercut what was a pretty good working system. It was not an accident, it was full on dliverate and crimianl in order to be able to pull all decision into Boeing and then contgrol them so no outsdie interfearance was doing to make them actauly do things right. Boeing has not paid the price at all for this, the mgt that was in charge got off with 10s of million of dollars and the curern managment will walk away with 10s of millionns of more regardless of hwo they perfomnr.
          I have been fired from more thanone job when in fact I was doing tghe work and was left high and dry monetary wise. Boeing managmen has not suffed diddly.

          Pilots: They are a victim of the systgem. The system tells them when, where, what, how and the stardards to be met. No pilot can rent a simularo and practice the real core of his job. That is dictaes by the system he flies in.
          Since AF447 its been finally reconized tht pilot need core skills. Some are implemnting that more succesully than others.
          They acualy had to reprogrm Simulaotr so that they could desmonsate a stall.

          Past that even, they have bells, whistles , voices that they know do not work but were allowed onto the flight deck by a whim not science. Anyone that has work construction is familiar with the first clang backup bell, then the horns, now flashing lights and whoops and they still do not work.

          Its all got a long way to go.

          Boeing doe snot want to change the system of how inspectors work, so no they have learned nothing. They want full control so they can repeat the disaster they just went through. Just gloss this over and forget what happened.

          • TW, nothing you’ve said here changes the point of my post. We have to look at all sides. As soon as we indulge in the blame game, that goal becomes compromised.

            It’s why the NTSB does not assign blame for the purposes of liability or criminality. That is for the justice system to decide. If you get caught up in your individual bias or hatred, it just blinds you to the truth. You only see the side that confirms your belief.

            Instead the NTSB looks for all relevant factors of contribution, leading to determination of significant causes. But always with an eye of improving safety rather than punishment.

            You can’t mix those two. The FAA is charged with enforcement. They have taken action against Boeing when deemed necessary.

            Boeing is also being investigated by the Justice Department for possible criminal conduct. Many staff have already been deposed. So we will see what comes of that. But it’s by no means a preordained outcome.

          • Rob: What you call the blame game is a cop out, standard politico speach.

            The core trigger for this was Boeing and its criminal actions in the design of the MAX MCAS. Period.

            It was not an accident, it was deliberate and knowing action.

            Its no different that you design a car with breaks that will fail, then sell it. Is there an emergency brake? Yep. Can you deploy it in time and do you realize both your brake circuits are gone?

            You clearly do not follow aviation, there are hundreds if not thousand of incidents that have proven pilots have issues.

            There are whole program in place working on that, there is shift in training to address that.


            To say we do is purely a crock.

            Boeing is fully aware of all the issues as well as aware of ALL the AOA failures that they so selectively cherry picked the data on.

            All your sophism is not going to change that.

          • Fortunately for the world, criminal actions are not for you to decide. I’ll wait for the results of the investigation.

            The rest of your diatribe is the usual attack on anyone who disagrees with your pre-existing views. You assign absurd views & reasoning to others, that no one here has ever even mentioned, apart from you.

            There is no learning or value or exchange of knowledge or views, in your attack. But it’s the norm for you so I’ll say no more.

          • You try to argue against facts, you loose.

          • How do you explain why these two crashes were in 3rd world countries and nowhere else. On one of the planes that crashed, the previous flight had a pilot in the jump seat and he knew what action to take whereas the captain and first officer were in the dark.
            Poor training was a primary cause but many don’t want to assign blame to the pilots, but throw all the blame on Boeing.
            Many MAX’s around the world were flying with no incidents.
            The 737 is a great plane and with the corrections made, it will go on flying with the world’s major airlines.
            Every OEM learns from their mistakes, it’s sad that so many people died, but poor training and maintenance contributed to these crashes.

          • Steve, you’re absolutely correct, but two important ancillary points:

            1. Even if pilot error was involved, that doesn’t excuse Boeing from the faults that occurred. It’s not a binary/logical “OR”, it’s an “AND” operation. The failures were sequential and the accidents required all of them to form the chain of events that actually occurred.

            2. The random pilot testing in December showed that it wasn’t just foreign pilots, there were problems noted across the spectrum of all pilots. Sullenberger also made this point in his testimony, he noted it was possible for a similar accident to happen in the US as well.

            I recognize your frustration at many of the anti-MAX comments made here, and I share it. But you can’t allow yourself to be goaded out of objectivity, by the subjectivity of others. An honest appraisal is the most beneficial..

          • @Steve

            “How do you explain why these two crashes were in 3rd world countries and nowhere else.”

            Sheer UNluck.

            AoAs fails all over the world. And these fails in MAXs happend by unluck first in these two planes.

          • “”How do you explain why these two crashes were in 3rd world countries and nowhere else””

            One AoA sensor was repaired in Florida.
            Tell me why the FAA didn’t close the shop earlier.

          • Steve:

            Care to explain the AF447 crash? Oh that is right, it was off a third world country.

            How about the UPS A300 going into (Alabama field?)

            How about the 767 Crash in Houston?

        • Rob: It is such a pleasure to read your comments and opinions on this complicated subject! I admire your objectivity and how level-headed and reasonable you are.

          • Thanks Muhammad! I know there are other readers out there who are trying to understand all of this, just as I am.

            I try to share what I’ve learned and explain as best I can. Obviously I’m not the only one, many of the commenters here make substantial contributions to the discussion.

            I don’t mind that critical views are presented, but I think it’s important to have balance and some fact-checking as well.

        • “Astute observers are pointing to a more holistic approach, that looks at the combined transport system of man, machine, and interface. In that system, human failures are responsible for ALL incidents, whether fault is found in aircraft or pilot. ”

          Empowerment counts.

          A single pilot failing can only crash a single plane.
          A single engineer failing should be caught ( befor it crashes a plane).
          A hierarchy failing ( by chance, through intentional acts.) turns into mass killings.

          • The pilot testing showed that the issues occurred across a full spectrum of individuals. Those problems have universal causes that don’t occur in just one pilot. That’s why training will be required across the fleet. There is similar potential for incidents, whether the failure is from pilot or manufacturer.

            The allegation of intent is a subjective opinion, as yet it is unfounded. We will see if the criminal investigations find evidence of it.

        • “How do you explain why these two crashes were in 3rd world countries and nowhere else. ”

          Low exposure for US airlines: The majority of (early) deliveries was to the kind of airline that had the crashes.
          ( was this intentional or just chance?)

          “On one of the planes that crashed, the previous flight had a pilot in the jump seat and he knew what action to take whereas the captain and first officer were in the dark.”

          The jumpseater had zero workload. And his findings weren’t instant. That his information did not propagate was a major process failure.

          • Uwe, the IG report shows that 12% of US market MAX orders had been delivered, while 7.5% of overseas market orders were delivered. This more or less follows the sequence of order bookings that occurred.

            This corresponds to a 2 to 1 ratio of aircraft flying in overseas markets vs US. So the odds did favor an accident occurring there. But we also know the first accident was a maintenance failure of AoA rather then random.

            In any case, the implication that Boeing intentionally sent aircraft to the overseas market first, as some sort of test, is false.

    • @Rob

      Jeeezzz… “The MAX will be safe. It was considered safe before the accidents.”

      By whom? By Boeing publicity?

      • It was considered safe based on no incidents since introduction, as well as the legacy of the previous 737 models. That is well documented. So it’s reasonable to conclude it will be safe again. That is the view shared also by regulators and airlines, as they’ve said publicly.

        • Clearly once all the issues are cleared up it will be as safe as it was.

          Of course it cost 347 lives to get it that way.

          Interesting that history repeats itself (if you don’t learn from history you are doomed to repeat it)

          It took two 737 crashes due to rudder issue to force Boeing to fix the problem.

          Good news was it only took one 767 crash and Niki Lauda to force Boeing to fix the 767. Only 223 that time.

        • @Rob

          Two crashes showed how UNsafe MAX was.

          But you are repeating after Boeing publicity that MAX was a safe aircraft.

          I’m speechless.

        • “”It was considered safe based on no incidents since introduction. That is well documented. So it’s reasonable to conclude it will be safe again.””

          It is well documented that Boeing cheated in their hazard calculations, which they self-certified too.

          Rob, how much coffee did you drink to come to your conclusions?

          • An aircraft does not accumulate 4,000-plus orders if it’s considered unsafe. So quite obviously, it was considered safe before the accidents.

            The accidents identified flaws mostly related to the design of MCAS. Those flaws have been fixed. Most in the airline/pilot community also understand that the pilots also played a role in the accidents, such that additional training is needed.

            So if the aircraft was considered safe before, and if the flaws in MCAS have been addressed, and if pilots will receive additional training, then it follows that the aircraft will be considered safe again.

            You and Pablo disagree because you start with the assumption that the MAX was never safe, is inherently unsafe, and therefore can never be safe. That’s up to you, but it’s unlikely to be the mainstream view.

          • @Rob

            “You and Pablo disagree because you start with the assumption that the MAX was never safe, is inherently unsafe, and therefore can never be safe. That’s up to you, but it’s unlikely to be the mainstream view.”

            MAX never was safe because had MCAS. Enough said.

            But by your book MAX was always safe in spite of having MCAS. Strange.

          • @Rob

            “An aircraft does not accumulate 4,000-plus orders if it’s considered unsafe.”

            You forgot to note that those orders took place before two deadly crashes – before came to the light flaws in design of MAX, including MCAS in first place, flaws in safety culture in Boeing and flaws in certification in FAA.

            So those orders were based on a strong lie.

          • Pablo, you’re trying to define the aircraft entirely in terms of the accidents. But it had a career before and will have one after. I know that makes you angry. I’m sorry.

            BOC, in cancelling some of their MAX orders, were careful to say it wasn’t due to their confidence in the aircraft, which remains strong. They consider it safe. They have considered it safe both before and after. This is what I meant by my comment.

            That’s not the same as saying MCAS was safe. We know now that it wasn’t. But the MAX is not defined in terms of MCAS, or its other flaws alone. That’s why it will be recertified and continue service.

          • @Rob

            “you’re trying to define the aircraft entirely in terms of the accidents.”

            Accidents and incidents are the measure of safety in aviation, or any other branch.

            Not smooth publicity words or sales goals or painting.

            MAX since introduction to service was not a safe aircraft by any means.

            It could be safe in a future but had lost this opportunity by not addressing other flaws regards stabilizer movements.

    • “The MAX will be safe. It was considered safe before the accidents. ”
      ( that “safe” assumption has been show as faulty.)

      Your Logic:
      All Cretans are liars. I am a Cretan. 🙂
      Best to view your statement as too distinct fully unconnected sentences.
      “The MAX will be safe. ”
      Hope expressed

      “It was considered safe before the accidents. ”
      a misjudgment.

  8. The european regulators drug their heels out for a year as they are trying to harm Boeing (as with the Embraer merger). It’s really that simple. The FAA didn’t want to give a single go ahead, and the Euro’s detest the American competitor.

    The required follow on changes within a year are just silly. But so is the risk involved which the Euro’s are committed to in creating hydrogen powered civil transports. That will cost more lives and make travel expensive, but it will feel great for some to see it.

    Look at how dumb the Canadians must believe pilots are;

    “To avoid such severe distraction and confusion, Transport Canada wants Boeing — before the MAX’s return to service — to include in the flight manual instructions for how to pull circuit breakers to stop the stick shaker.
    The circuit breakers are in an overhead panel in the 737 cockpit. Transport Canada said it will require Boeing to add “collars” to the stick shaker circuit breakers to distinguish them from others in the vicinity so they can be quickly identified in an emergency.”

    • “”The european regulators drug their heels out for a year as they are trying to harm Boeing (as with the Embraer merger). It’s really that simple.””

      After the Lion Air crash Boeing knew exactly what was wrong, but they only came up with a stupid buletin. The FAA made crash calculations and found out that many more crashes will happen and still didn’t ground the MAX.

      The loss of ET302 was a crime. It’s really that simple.

      EASA wasn’t even allowed to enter the US for flight testing LOL. I don’t think Boeing will get away with this.

      • Leon:

        I would like to see where EASA is not allowed in US. With Covd there might have to be steps and measures but not allowed?

        All that is needed regardless is to program a European based MAX to the same as an USA MAX MCAS REV 2.0 (with the new computer configuration) and you can test it at your hearts content from the comfort of you own living room.

        You would have a line up of European Airlines offering theirs up so they can get it back in the air (the wiring issue has to be addressed as well )

        This is not something that will not be duplicated and they get all the data to review to see how the tests were done, what was done. Its better than being there as you get to see at your leisure any holes in the testing rather than being in the weeds.

        • Leon is right that EASA members were not allowed to enter the US due to the travel ban. There is an exception for visits in the national interest. I would think this would clearly qualify, and I’m sure the FAA would have asked.

          So my guess is it was either denied by the Trump administration, or they insisted on a quarantine period (standard is 14 days) that was unacceptable to EASA.

          I can see no reason why Boeing would not have wanted the opportunity to involve EASA. It’s not like hiding a problem would not quickly be found on later inspection.

          Other regulators could test an aircraft supplied by Boeing, if they were willing to allow that flight to their own country. So it seems like there will be a solution at some point. In the meantime, EASA and CTA have agreed to conditionally follow the FAA certification. That will not happen until September anyway.

    • The FAA and Boeing both objected to the circuit breaker collars, so they will be an interim measure until Boeing can propose another mechanism.

      The concern of the CTA was that pilots received both stick shaker stall warnings and overspeed clacker warnings at the same time. But notably, they occurred on opposite sides of the aircraft, so they were both important for pilot awareness of what was happening. Each was relevant for the situation that had developed.

  9. Will the MAX pass the FAA flight test?
    This is more a test for the FAA, every other regulator will watch them.

    • Will the FAA require all planes to have active sidesticks (as columns are on some airplanes)?

      • Not until its proven that passive side stick causes a crash.

        I agree with active, both Auto Throttle and controls.

        Airbus does not have active Auto throttles, but they have a better safety system under the logic tree as well.

        I call the passive side sticks Bump Steering, I did not like it driving big rigs and I doubt I would like it flying.

  10. I wonder if all this means that recertification passed OK, then each and every MAX grounded must go through an engine/electronic system upgrade? Wow!

    • Yep. No different than any other software upgrade.

      Plus the wiring fixes and oh by the way, clean that FOD out of the fuel tanks.

      Yep, Boeing really gets it, garbage in the fuel tanks of a brand new aircraft.

      Well if they can attempt to deliver crud to the USAF on the KC-46, why not here?

      Yes sir ree Bob, Boeing sure has learned their lesson.

  11. In the 2 dramatic crashes of the B737 MAX’s, it apparently was the MCAS issue, according to Boeing and FAA, with B announcing that there was a fix of the MCAS coming soon after grounding. The fact is, that whatever new MCAS they install, the main issue with the aircraft remains to be the Structural and Aerodynamics of the aircraft and in diligent training of all future pilots on the aircraft.
    I wish them luck in their revised experiment, but I shall never put foot on one of these Birds.

    • Norm: While I am full in agreement that MCAS was criminal – both from my experience as well as Bjorn and Peter Leme, I see nothing on the basics of structure and aerodynamic as an issue.

      I do see the manual trim an issue, that goes back to all 737s and I would like to see response on that.

      • BJORN & PETER, I should have emphasized the repositioning of the engines in the forward section of the wings, may have played a role in altering the stability of the aircraft. Totally agreed on the MCAS being the proximate cause.

        • The repositioning was actually a minor shift. You can overlay the scaled drawings of NG and MAX (people on StackExchange have done this) to see there is a shift forward and up, but it’s a matter of 8 to 16 inches at most (more up than forward).

          Together with the increase in the nacelle size, a minor shift in the center of lift was created when the underside of the nacelles were exposed in a nose-up attitude. But nothing that would impact the inherent stability of the aircraft. It just caused a reduction in column force during a climb, increasing with increasing angle of attack.

          The inherent instability argument has been debunked numerous times. But I knew it would be raised again at certification.

          • Rob:

            You have the facts wrong.

            What it did was at extreme edges of the envelope was to cause more pitch up than there was before.

            MCAS was supposed to only kick in at stall, not at any other time.

            Due to the insane method of implementing it, it could and did kick in when one AOA imputed bad data.

            Any engineer that could not see the flaw should be put to cleaning latrines.

          • TW, this is a misunderstanding on your part, but it’s central to many of your positions, and I know I’m not going to change your perspective through discussion.

            So I stand by my description, as it is consistent with everything we know about the development and behavior of MCAS. I have faith that others reading will understand.

            Also the re-certification should confirm this, as I believe MCAS is unlikely to be determined as a stall prevention or identification system. If it is, then I’d be wrong, Boeing will have lied, and there’d be ample topic for further discussion.

    • Interesting, a MAX 7. I presume almost all parts and systems are identical to the MAX 8, but since it was the MAX 8 involved with the catastrophes, I would have thought they’d be using the 8. Before testing is over, I’m sure the MAX 8 will be used extensively.

      • It would be a good one to have Bjorn address, is the MAX7 the worst offender to pitch up or the best?

        We can hope its the worst. Aerodynamics on longer vs shorter for the issue is beyond me.

        Reality is that any pilot knows what to do with a stall and the inanity of putting in a smoothing function for an area of flight that is gross reaction (dump the damned nose) is beyond me.

      • Didnt they never fully certify the Max 7 before the grounding , so still had test equipment on board. May not still have the original Max 8 so equipped as that first certification was back in 2017.

        • As far as I know you are correct.

          Other than shorter though it is an exact -8 copy.

          • The -7 can’t be an exact copy of the -8 for the precise reason that it is shorter. The shorter tail causes a ripple effect of required changes to the airframe and various systems, not the least of which are the control system settings. Most changes are small, but some are not so small.

          • “”The -7 can’t be an exact copy of the -8 for the precise reason that it is shorter.””

            Nobody knows what Boeing did, but we know that Boeing is lazy and cheap.
            Boeing made stabilizers and elevators stronger but forgot to make the jackscrew stronger too. Why? Was it because of $$$?
            The accident reports revealed that the jackscrew was too weak!!! Is the jackscrew still too weak?

            If the different MAX versions have different MCAS degrees. every MAX version needs to be certified separately.
            So why start with the MAX-7??? Makes NO sense!!!

            FAA and Boeing doing certification flights ALONE when both cheated in the past and killed people!!!

          • -700 NG seems to have been rather bespoke structure wise. unpleasant for a subtype that today would get minimal interest in -7 MAX upgrade.

            the -7 MAX “MK2” is said to be a minimum change shrink of the -8 MAX.

        • If I’m a regulator and want to flight test I tell Boeing which model I want to fly, not fly what Boeing wants me to test.

          You have to imagine this, the criminal tells police where to search for fingerprints and where searching is not allowed LOL

          EASA wanted to flight test without MCAS for a reason and were not allowed to enter the US … haha

          • @Leon

            EASA pilots wasn’t allowed to enter US because of sanitary Covid-19 restrictions. That’s all. When situation will clear up with a time EASA will fly and I hope will fly it extensively.

          • Pablo,

            do you really think EASA will ground the MAX again after they ungrounded it?
            If EASA certifies the MAX without flight testing they are not better than the joke FAA. EASA trusted FAA before and it led to death of European citizens.
            EASA is sitting in Germany. A German vaccine company was allowed to enter the US.

          • @Leon

            It would be a not funny joke if EASA would ungrounded MAX without flight testing.

  12. For the Chicago/O’hare DC-10 crash, the pylon removal process wasnt approved by the FAA or McDD. It may have just been a typo to say so.
    ” In the end, this accident was traced to an ill-advised engine/pylon removal procedure, approved by McDonnell Douglas and the FAA”

    ‘The lessons learned’ from the FAA report on the NTSB investigation gives the details
    ” Additionally, removal of the engines and pylons as a unit was NOT an approved Maintenance Manual procedure.”
    “The Maintenance Manual did not provide instructions for removal of the engine and pylon as an integral unit. To facilitate the time required for bearing replacement, American Airlines developed a procedure using a forklift to remove, support, and replace the engine/pylon assembly.”

  13. They are testing with MCAS.
    With MCAS the effects are less on a MAX-7 because the distance between stabilizer and center gravity is smaller than on MAX-8 and -9.
    Testing with a MAX-7 makes less sense, but it’s better for FAA pilots to start with an easier to fly MAX-7.

    Will the FAA test without MCAS?
    Without MCAS the effects should be stronger on a MAX-7.

    • Leon:

      You are contradicting yourself.

      If sans MCAS the affects are stoner, then the MAX7 is indeed the one to go with as it needs it even more (if its really needed at all which I think it is not)

      MCAS 2.0 can no longer have the affect MCAS 1.0 had, so its less total authority as well as less how fast.

      Keep in mind, it only kicks in (now) during a totally abnormal flight condition (Stall)

      I have never heard of a LCA stalling. Some that were totally out of control may have done so but that would be secondary to total loss of control not stall itself the issue.

      Trust me, if you stall and aircraft subtly is not part of how you react. You dump the nose as hard and fast as you can.

      • It’s all about “without” MCAS and how turbulent conditions could be. That’s why there are regulations for this.

        Boeing was in the self-certification business and did a bad job. If MCAS is a stall system it needs to be designed different. The FAA will reveal this, otherwise other regulators will do it.

    • @Leon. Ok, so there is a reason to go with the MAX-7 first. Thank you.

      • test equipment.
        The Max 7 never made it through full certification before grounding. Max 8 and Max 9 were only variants to get to EIS.

    • Leon,

      “Without MCAS the effects should be stronger on a MAX-7.”
      I agree that this part of your post is correct.

      All three models experience the same ANU pitching moment change as a function of AoA and airspeed, but the MAX-7 will require greater stabilizer deflections to counter this pitching moment change because it has the shortest tail.

      However, the rest of your post relies on assumptions that you do not know to be true. None of us do. While we all have read about the MCAS stabilizer deflection schedule ad nauseam for the past year or so, the reports were only about the MAX-8 because it was the only model ever involved in the crashes. You do not know that MCAS changes the stabilizer incidence angle on the -7 or -9 according to the same exact schedule as it does for the -8. None of us do.

      So, does MCAS affect the -7 more or less than the -8?
      None of us know.

      Is an MCAS failure easier to handle on a -7 than on a -8?
      If MCAS fails to activate when it should, then no.
      If MCAS erroneously activates, then again, none of us know.

      It seems like you are again trying to imply that Boeing is cheating or trying to cover something up by using a MAX-7 for MCAS re-certification instead of the -8. Sorry, not falling for it.

      • We only heard about the same MCAS degrees in the past, not different degrees for different MAX versions. Also it was only about the MAX-8 because only few MAX-9 were in service.

        Flight testing is very easy, it’s about printing the pitching curve, it should be linear according to regulations. They won’t test in turbulent conditions which will cause the real problems.
        The problem is the pitching curve might not be linear, that’s why Boeing invented MCAS and is hiding the data.
        If the pitching curve without MCAS is not linear the MAX won’t pass the test. Every regulator knows this and the FAA should look for this. Will the FAA test without MCAS, or do a lazy job nobody else will accept?

        Other regulators are watching this. THEY grounded the MAX-8 and -9, not the FAA. So testing the MAX-7 is kind of strange, isn’t it.

        • All MAX models were grounded, so all MAX models will need to be certified. MAX-7 is not at all unusual. Especially if as Duke says, the certification of the 7 was on-going at the grounding.

          The pitching curve is another resurrection of the inherent instability argument, which has been thoroughly debunked. We would not be at this point in the process if the MAX had stability issues.

          What could arise, is MCAS being viewed as stall identification or prevention. I think that’s unlikely after all this time. Or that MCAS is too slow to back out when the nose is dropped by the pilot, leading to over-correction. Both issues were raised by JATR and will be checked by the FAA, I’m sure.

          • Leon:

            I don’t know where you get turbulent condition from.

            The MAX handling difference of excessive pitch up only occurs at a stall and more so an accelerate stall.

            Unless by turbulent you mean air separation that occurs in a stall, turbulence as in rough air has nothign to do with it.

            My issue with Boeing is they took a perfectly good working aircraft and made it a lethal killer. Not miner handling differences.

          • @TransWorld

            It’s about how un/stable MAX is, how easy it will be prone to stall without MCAS. In smooth air could fly acceptable, but in turbulent air it could be nasty and enter into stall conditions with easy – which is unacceptable for an airliner.

        • Leon,

          This sentence:

          “Also it was only about the MAX-8 because only few MAX-9 were in service.”

          is essentially the point that I made, and it explains your first sentence:

          “We only heard about the same MCAS degrees in the past, not different degrees for different MAX versions.”

          While the MAX-7 is very similar to the -8, -9, and even the -10, it is not an identical aircraft. The shorter tail significantly affects how the aircraft flies. The static margin is most certainly different for the -7 than on the other derivatives. Also the elevators and rudder will require more deflection to achieve the same pitch and yaw rates, so the PCU gains are most certainly different. I wouldn’t be surprised at all if the MCAS schedule on the -7 has greater deflections than on the -8.

          Could the -7 MCAS schedule be the same as on the -8? Certainly, but none of us know for sure. The absence of any statement about -7 or -9 MCAS is not proof they are the same as the -8 MCAS. So the idea that Boeing chose the -7 for recertification testing because they will somehow have an easier time hiding an incorrect MCAS activation from the regulators is pure nonsense.

          What is not nonsense, however, is that the sudden ANU pitching moment change at high AoA due to the engine installation is larger in proportion to the stabilizing influence of the tail on the -7 then on the longer tail derivatives. This is because of the smaller tail volume due to the shorter tail. Thus, flying the aircraft without MCAS active in the regime where MCAS is needed will be more difficult on the -7 then on the other derivatives. The -7 will actually provide a more severe handling problem that MCAS will need to address during the test flights. Well, so much for Boeing “cheating” to make the tests easier. It’s pretty clear that if Boeing wanted to cheat, they would’ve chosen the -9 instead.

          “If the pitching curve without MCAS is not linear the MAX won’t pass the test. Every regulator knows this and the FAA should look for this.”

          This is a misconception that has been thoroughly debunked in this forum. The 737 MAX is not the only airliner to exhibit “bad” pitching moment curve behavior that requires an augmentation system for correction. For the 737 MAX it came down to the magnitude and location (close to stall) of the bad behavior. Mostly the location. So what if augmentation is required? It’s not a show stopper and regulators are not afraid of it. This kind of thing has been done and certified before.

          The facts just don’t really support your opinions here.

          • “”the idea that Boeing will somehow have an easier time hiding from the regulators is pure nonsense.””

            Other regulators are not allowed to test!!! Boeing hid data, obviously EASA didn’t believe Boeing and EASA want to test without MCAS.

            “”It’s pretty clear that if Boeing wanted to cheat, they would’ve chosen the -9 instead.””

            The FAA is not testing without MCAS.
            EASA wanted to test without MCAS and wasn’t allowed to test!!!
            What are other regulators thinking about this, especially when Boeing cheated in the past.

            “” The 737 MAX is not the only airliner to exhibit “bad” pitching moment curve behavior that requires an augmentation system for correction. This kind of thing has been done and certified before.””

            If this is nothing special why is Boeing hiding the data? Why did Boeing kept it secret and didn’t tell FAA everything? Boeing self-certified MCAS which killed many people !!!

          • Leon,

            It’s been widely reported that EASA will indeed be allowed to test the MAX if they so choose. Either way, the FAA will provide EASA with the data from their testing.

            It’s also been widely reported that Boeing has extensively tested the MAX without MCAS months ago, and have provided the resulting data package to the FAA. So much for Boeing hiding the data.

            If you are going to accuse Boeing of hiding and keeping secrets, please enlighten us all about which aspects of MAX MCAS, pitch stability, or stall characteristics that Boeing is currently hiding from the authorities. I’m certain we would all be very interested in your breaking news on these subjects.

          • “”EASA will indeed be allowed to test the MAX if they so choose. Either way, the FAA will provide EASA with the data from their testing.””

            Nice wording “if they so choose”. I doubt EASA will flight test the MAX. Fact is EASA wasn’t allowed to enter the US.
            EASA is sitting in Germany. A German vaccine company was allowed to enter the US.

            I doubt the FAA did flight testing without MCAS.
            I did regulation work before and would never let the manufacturer take part during my testing. It’s the same as if police let the criminal take part in checking the crime scene to show police test skills.
            The FAA did flight testing with Boeing pilots together. I question myself if the FAA pilots even flew the plane.
            There is a reason why people and regulators don’t trust the FAA anymore. The FAA is a joke. Did the FAA really test a MAX-7 LOL

            “”Boeing has extensively tested the MAX without MCAS months ago, and have provided the resulting data package to the FAA. So much for Boeing hiding the data.””

            Boeing is not a regulator and can’t do a regulator’s job. They did that in the past and we know where that led to.
            It was reported that regulators were complaining again and again that Boeing didn’t provide all documents. I read recently that the FAA still didn’t check all documents, therefore they can’t say that the documents are complete now.
            The IG documented yesterday that Boeing hid important documents to fool the FAA. How is that even possible???

          • Leon, just to clarify, the IG report says that Boeing did not adequately report the late-stage MCAS changes to the FAA. The data were reported, but across several documents and not in a cohesive manner that would permit a full review.

            Thus some FAA certification managers never became aware of them, while others were. But there was no allegation of intent or hiding documents.

            Boeing did fully report and explain the MCAS changes to the FAA flight test engineers & pilots (who absolutely do fly the aircraft in certification checks). They tested MCAS at both the original and increased authorities. But that team, in reporting their certification findings, also did not communicate the changes they had tested to their colleagues.

            So some staff in the FAA knew and some didn’t. The FAA has acknowledged there was a failure in communication, both between FAA and Boeing and within the FAA.

            The report also says that FAA delegated both the flight control and stabilizer certification plans to Boeing, while retaining the safety assessments for both. However neither Boeing nor FAA questioned or tested the multiple activation scenario for MCAS. The accepted belief was that multiple activations were not significant because pilots would respond correctly to the first activation.

            One thing that has become apparent, is that the statistical classification and presentation of systems can mask the reality of how they physically function. The technical familiarization meetings for MCAS occurred near the beginning of development.

            After that, there was really only statistical consideration of safety. I think something is lost by limiting the perspective to statistics. But that is the method used to evaluate risk.

          • Rob means that The Seattle Times, Flightglobal, Courthousenews and others all at the same time reported something wrong …

            Seems Boeing can’t even put documents in the right order together. Makes sense, Boeing never provided an software audit before too. No wonder that the FAA outsourced certifications to Boeing because of all the garbage they got from Boeing.
            Last December other regulators clomplained about Boeing documents too and now I understand why the FAA still didn’t check all documents. Must be a mess.
            Boeings bulletin after JT610 was a mess too. Not useful as a checklist in flight.
            The FO of JT610 was overwelhmed with Boeing’s checklist mess too, then the Captain took the checklists but his lifetime was running out.
            Why is Boeing only able to deliver garbage.

          • Leon, if you read the report rather then the reporting, you’d realize the truth of Scott’s words regarding reporting on the MAX. In many of the articles you mention, it becomes clear that the headlines and conclusions are drawn by the reporters, but are not given in the report itself.

            Seattle Times (as usual) is the least biased, but even they have made accusations of deliberate behavior that are not founded in the report:

            “Inspector General report details how Boeing played down MCAS in original 737 MAX certification – and FAA missed it” — note that this is basically true. But with regard to the accusation of deliberate actions “close to deception”, the report makes clear that FAA officials concurred that the original concept of MCAS was a system revision of speed trim and not an area of emphasis.

            In hindsight, this can be viewed as an attempt to conceal a system that was known to be hazardous. But that was not known in 2012-2013 when the meeting occurred. MCAS was only a simulator adjustment at that time. The true faults were introduced much later in the development and implementation process.

            “Critics say IG’s report let FAA off the hook in certification of Boeing’s flawed 737 MAX” — note that this is reporting on the opinions of others, mostly those in Congress or the families who wanted the report to be much more critical. But the purpose was to establish a factual timeline, not to establish fault.

            The absence of the establishment of fault is clearly disappointing for those groups. But I think the report is accurate in producing a picture of what actually happened. It was complex and there isn’t a simple or single player to blame. Just as was true of the accidents themselves.

            We know that a safe implementation of MCAS was always possible, as it has been done now. So the real focus should be on how it was allowed not to be. That is where we can learn and improve, and that is the true value of the report.

          • Leon,

            Perhaps EASA won’t conduct their own flight test, or perhaps they will, it’s up to them. Back toward the end of 2019, reporting indicated that whatever rift had existed between the FAA and EASA and other regulators with regard to MAX re-certification had been largely bridged. Personally, I always thought that the rift was exaggerated, but whatever. About this same time, I got the sense from the reporting that EASA was much less hard over about performing their own certification tests. EASA’s view on this whole thing hasn’t been static. Instead, it has evolved, just like the FAA’s view and Boeing’s view has also evolved over time.

            Again, EASA will be able to test fly the MAX if they choose. I’m now thinking that they will probably choose not to, and they will re-certify the MAX based on the data gathered by the FAA and recommendations made by the FAA. As an aside, it makes perfect sense these days that a vaccine company would be granted an exception to travel restrictions whereas EASA might not get one. I think we can all agree that aircraft regulators are not as essential as vaccine researchers/producers during a global pandemic.

            Your comparison to the police is a useless straw man argument. When you did your “regulation work”, did you test the devices you regulated without any prior knowledge of how they functioned or were constructed? Did you not have access to spec sheets, operation instructions, and design documentation from the manufacturer that demonstrated likely regulatory compliance? Perhaps the devices you regulated were so simple that you needed no documentation to conduct your testing.

            Well, aircraft are not that simple. Before the FAA even considers testing the aircraft for certification, they demand that the manufacturer provide them with proof that the aircraft will likely pass certification testing. This is part of the design documentation, and it contains the relevant data pertaining to whether or not the aircraft will meet the standards. The flight data taken 8 months ago by Boeing without MCAS and subsequent analysis would be included in this documentation. So, whether or not they actually tested the MAX without MCAS during these last 3 days of final certification tests makes no difference. The FAA already has the relevant data.

            As far as incomplete documentation goes, yes this was a persistent problem with Boeing, and may still be in the future. It is an indication that Boeing and the FAA had grown way too close, where in order to expedite the schedule, the FAA would review and give approval on issues where the data was taken and analyzed, but the documentation was not yet complete. However, in light of what happened with the MAX, the FAA put it’s foot down for the re-certification effort and pretty much refused to start any review until the complete documentation was submitted. This is “to the letter of the law” as opposed to the way it was before, which was more “to the spirit of the law”. As we can all imagine, the design documentation is extensive and can take a considerable time to review. Just because the FAA hasn’t worked through all the documentation yet, does not mean that it is incomplete.

            Finally, Rob did a good job calling you out on your “interpretation” of the IG report, so I don’t really need to address it here.

          • “”Before the FAA even considers testing the aircraft for certification, they demand that the manufacturer provide them with proof that the aircraft will likely pass certification testing.””

            The FAA can’t even flight test alone, need babysitters, what a joke.

            This all doesn’t match and doesn’t give me a good feeling. There is still so much wrong, everybody knows it.

            I wonder what other regulators will do. I don’t expect much from EASA, are they a joke too.
            If the MAX designers are clowns who are guided by monkeys, what are FAA and EASA. I hope there is one regulator who shows that he is the boss. The flying public deserve this.

          • The FAA can’t even flight test alone, need babysitters, what a joke.

            This all doesn’t match and doesn’t give me a good feeling. There is still so much wrong, everybody knows it.

            I wonder what other regulators will do. I don’t expect much from EASA, are they a joke too.
            If the MAX designers are clowns who are guided by monkeys, what are FAA and EASA. I hope there is one regulator who shows that he is the boss. The flying public deserve this.

            You should stick to facts. A post like this destroys your credibility in this forum.

          • Mike,

            you want to have facts? We are talking about this for over a year. The facts are known and you know them too.

            If Boeing would follow all regulations, everything would be fine, JT610 and ET302 would not have crashed. But as we all know, Boeing isn’t following regulations, Boeing is cheating if they can save some $$$.

            That should be no problem, a strong FAA should find the mistakes with ease, but they are weak and not doing it. Why? Boeing and FAA are Best Buddies. After Dickson is fired, will he get a Boeing job?

            If the sim is 100% playing the MAX behaviour, I can show that MCAS isn’t following regulations. Every regulator can invite me, it’s not difficult, every regulator should find the mistakes themselves. Maybe because it’s so easy even the Ethiopean sim was faked by Boeing.

            Boeing is a joke, FAA is a joke, but Best Buddies.

  14. Boeing has done many 737 test flights over ghe last 12 months. The question is what they are testing now? And what is thhe role of the FAA in this test?

    What changes have been made and does this MAX meet 2017 certification requirements & JATR recommendation? Or is it a confrontational PR / political offensive?

    • Reporting is these are certification test flights with an FAA pilot. Standard certification testing but expanded with special testing for aircraft handling surrounding MCAS. Normally it would be one day of flights, this is 3 days so the FAA may be running test points for other regulators as well.

    • This is the joint FAA and Boeing test.

      All prior testing was to ensure that it would pass the joint test and or meet the specs that had been set out for it to meet (adding in the cross linked computers)

      Frankly its been done in the Sim and the fidelity going to be 100%, but also you never assume.

      Next steps will have the FAA fly the test with their pilots.

      Then of course the good house keeping stamp of approval is for Dickson (FAA head) to fly it. He of course is whats most important as he is so in tune with testing process.

      Data needs to be reviewed and all that passed onto EU and China etc.

    • To add in, the FAA will not put pilots in an aircraft until its passed the preliminary tests to confirm it conforms.

      They are not test pilots but confirmation.certification’s that it flies the way it should.

      Into that they will have reviewed Boeing data on its test flights and have satisfied themselves it works as advertised.

      If in their own flying they find an issue, then tests stop until its resolved.

      I think the fake out test (like an AOA going off the reservation) is done in the Simulator.

      Real stalls are flown in the test flights as they would be during any check out of the aircraft prior to the owner taking it for their own flight checks.

      The one they most will want to see is a turning power on stall (ala accelerated stall)

  15. Norwegian airlines has cancelds 97 Boeing aircraft and requested the cash back from Boeing .

    • Yea, they were in serious trouble before. Of course they have a ton of A320NEO on order to (that they can’t use)

      Be interesting to see ho9w Boeing is to blame for the RR 787 engines as Norwegian was the one that selected them!

    • Not that surprising, Norwegian has been struggling financially, with several affiliates filing for bankruptcy in April. I’m sure they need that cash back right now.

      • SACO pilots sure talked like test pilots a few decades ago, IMO too gung-ho though better than other regions

        Note simulators are not necessarily accurate, especially in obscure features.

        As for Iran sending recorders to France, it has readout ability and is at least relatively impartial, US and even Canada would be suspect in the eyes of Iranians, Ukraine wouldn’t have its own capability. The Netherlands are usually viewed as impartial (they investigated much of the shootdown of Malaysian 7 over the Ukraine, I forget who read out the recorders). Iran has been dragging its feet for months about transferring custody of the recorders, albeit it was a hotspot of COVID-19 from relations with Communist China who supply rockets that Iran’s proxies fire at Israelis.

  16. The test aircraft is fully instrumented, cabin is full of data collection equipment and engineering stations. There are pictures of it on-line.


    They have instrumented versions of the MAX 7, 8, & 9, or at least they did at the original certification. So may be flying all 3 over the next few days.

    • Looking at your reference, the Max 8 test aircraft N8701Q, N8702L, N8704Q went to Southwest ( now parked) . N8703J is waiting for delivery to Southwest, presumably now in passenger config.
      the Max 9 N7379E, N7201S are still with Boeing, N739EX is with Thai Lion Air

      • Duke, thanks for looking up the tail numbers. I offered those photos as an example of what is required for an instrumented aircraft, not that Boeing would use those specific aircraft. I’m sure they will have all 3 models available if needed, as before.

      • Hello Dukeofurl,

        Re: ” N8703J is waiting for delivery to Southwest, presumably now in passenger config”

        According to the Google Doc at the link below, maintained by a Seattle area plane watcher, N8703J (a 737-8), has since 1-1-20 conducted 10 “engineering flights for specific tests” (flight type code EWA), all with Boeing flight numbers, which is far in excess of the 3 to 4 test flights (flight type codes B1, B2, B3 etc.) usually conducted by Boeing before one or two customer acceptance flights (flight type codes C1, C2 etc.). Do you have another plausible explanation for these “engineering flights for specific tests” other than MCAS testing?


        The speed and altitude trace on Flight Aware for the latest of these flights on 6-16-20 looks a lot like MCAS testing to me.


        List of “engineering flights for specific tests” from 1-1-20 to 6-26-20 according to the Google Doc that I referenced above.

        2-21-20: N8703J (737-8)
        2-22-20: N8703J (737-8)
        2-24-20: N8703J (737-8)
        2-25-20: N8703J (737-8)
        3-12-20: N8703J (737-8)
        3-20-20: N8703J (737-8)
        3-24-20: N8703J (737-8)
        3-24-20: N918AK (737-9)
        3-25-20: N918AK (737-9)
        5-1-20: A40-ML (737-8)
        5-4-20: N8736J (737-8)
        5-6-20: N47517: (737-9)
        6-9-20: N8703J (737-8)
        6-12-20: N8703J (737-8)
        6-16-20: N8703J (737-8)
        6-26-20: TC-SOI (737-8)

        • I think Duke was just looking up the tail numbers as to eventual ownership. Not making a statement about whether testing has been done with that aircraft. It’s common for certification aircraft to be sold to customers.

          As to the nature of the testing, it would be similar to any certification test regime, but with added emphasis on the rewritten flight control software, as well as rewritten MCAS.

          The MAX is using all new software so may require additional scrutiny and test points. Plus there may be conditions requested by other regulators, which again is a new situation with the MAX.

          • Yes. They seemed to have been used for more than just delivery test flights. The last one as the link showed was mostly Southwest seating with some test instruments at cabin rear, that’s why I mentioned the likelyhood of that instrumentation now removed.

  17. @Leon. Ok, so there is a reason to go with the MAX-7 first. Thank you.

    • The issue is how many more debacles does Boeing suffer before the board cans the lot of them and brings in a new team that is focused on good and safe product first and their big bucks last?

  18. I’m afraid the only one making the decision on the max is the commodity called PAX.
    If they devide the won’t trust the Max and Boeing any more, that plane is done, finished. No airline can compete with lower booking/usage rates because it’s using a plane with a crash history.

    If the airlines see a significantly lower utilization on B737 Max routes, Boeing is in trouble.
    Especially now in an after Corona world with plenty of pilots and planes available.

    Before Corona, it was impossible to get airplanes and the grounding was a disaster for Boeing. Corona could be a double-edged sword for Boeing.
    It takes out the pressure on the recertification and grounding issues, but on the other side, it makes alternatives available.
    Any airline can call Airbus today and buy A320neos with deliveries in the next year.

    It will be intresting to see what will happen!

    • The cancellations that have occurred so far appear to be related to economics (canceling the purchase with no other in mind), rather than the desire to switch platforms. The view that no switches have occurred because the Airbus order book was full, is now being put to the test. Switching platforms would involve additional costs that airlines may not view as favorable right now.

    • Boeing has hundreds of MAX’s parked so they might be quicker to deliver pending the FAA test flights.
      The fact that the MAX was completely gone over and the regulators are giving much attention will result in a safe plane and the 737 model has done very well for decades.

      • That I agree with.

        It should never have come to this in the first place though.

  19. Boeing probably after 1,5 year finally prepared at least acceptable MCAS fix.

    FAA / EASA will do test flights and will see how un/stable is flying MAX without MCAS, how easy is not to enter into the end of “envelope” / danger zone, how un/easy is to recover etc.

    Let’s talk about elephant that isn’t in the room:

    1. unoperable (small & with inproper gearing) manual trim wheels in serious out of trim situation,

    2. single function cut-out trim stabilizer switch, instead of two independent switches (computer initialized inputs + engine electricity supply) like in NG.

    These flaws are ticking bombs for me, because not only MCAS can initialize uncontrolled stabilizer movements.

    I’m disappointed that nor FAA nor EASA aren’t pushing Boeing to fix them. At least one of them.

    These makes for me the MAX as unsafe plane.

    • EASA published clear requirements for re certification. Boeing and the FAA not discussing them, doesn’t make they are somehow going away, exempted, forgiven, overruled, excluded based on irrelevant statistics, by people unknowing, pressured, like it used to be. The core of this MAX drama.

    • Pablo, the interim ET302 report measured the trim wheel forces. They are operable under normal flight conditions.

      At high aerodynamic load conditions (overspeed or large mistrim), they become progressively more difficult to operate. So that will become a training point, to make sure the pilots know how to unload the stabilizer aerodynamically if needed.

      Also to experience the high mistrim forces in the simulator and emphasize the need to keep the aircraft in trim. Trim has been reliably automatic for so long, that this may be one of the skills that has eroded.

      As far as the cutoff switches, I agree with you, I was hoping they would revert back to the superior NG design. The regulators must have thought that wasn’t needed, but it would restore an additional safeguard at very little cost.

      • I’m with you on the cutoff switches Rob.

        It’s a no-brainer, you add another level of safety that hopefully will never be needed, defense in depth.

        I still can’t see any reason that they changed the switches in the first place, it runs counter to all of the rest of the thinking … “change as little as possible so that extra training isn’t needed”.

        • The reason they gave was that it reduced flight deck complexity for the pilots. That was a major goal of the more modern instrument design. But the trade-off in terms of the loss of functionality was large, in return for a small reduction in complexity, that likely wouldn’t be noticed by pilots accustomed to the NG.

          I looked at the switch control schematics for the two designs, to see if it could be easily reverted. It looked like they had simplified and reduced other components as well, so there wasn’t an easy way back. But I think had the regulators asked, they would have made it happen. I think it would have value to the pilots.

          • No aircrat should have to dump the nose to deal with a system you can’t use.

            Close to the ground is the last place you want to do a yo yo (dumping the hose in other words while madly cranking on the wheel which means your attention is no longer on flying the aircrat. )

            You also miss that if the motor seizes, the pilot to trim have to break out the clutch.

            That is close to impossible and may well be impossible for a female pilot.

            The yo you was the answer on the early jets, it should never have been allowed in the Classic 737 let alone any subsequent variants.

            Its the heart and sole of backup and a backup that works like that should never be allowed.

          • TW, note the yo-yo maneuver was not required in the accident flights, or in JT043. Just use of electric trim to unload the stabilizer before switching off. Also attention to airspeed. These are clearly issues that can be addressed via pilot training.

          • Can the STS system AND MCAS both be active at the same time, just a few seconds after takeoff? Which one would override the other?

          • @Richard Davenport

            Originally MCAS was a rough subroutine hidden in STS which could override standard routine.

            Now? Good question…

          • Actually Rob, there are tough female pilots.

            Like the one who delivered a Bristol Freighter

            And small fems have an advantage in fighter aircraft as females torsos tend to be shorter than male thus brain is closer to heart thus less reduction in blood flow under high acceleration.

            There certainly are small people, years ago Boeing started to look at range of pilot heights it should consider.

          • The common understanding is that STS and MCAS are integrated into one system, so that each is aware of the other, and their contributions would be an effective sum. I don’t know the exact logic employed. It’s also possible that STS has operational limits that would disable it at some point.

            MCAS is driven by a lookup table of airspeed, altitude and AoA. STS is a function of airspeed, it adjusts trim (within limits) to maintain speed, by altering AoA. Normally only a small adjustment is required for STS, whereas a larger adjustment is needed for MCAS.

            So taking these two things together, we can imagine that the STS contribution would be swamped by the MCAS contribution, once MCAS is triggered.

            Whether the sum is complementary or opposed, would depend on whether speed is increasing or decreasing. Increasing speed in a steep climb would mean the sum is opposed, decreasing speed would mean the sum is complementary (same direction). Constant speed would mean STS contribution is not changing.

            But of course we don’t know for sure. this is only a speculative and conceptual understanding of the basis of operation for each.

          • Also Keith, it was TW who made the remark about female pilots. I’ve seen tiny women bikers kick the crap out of much larger guys in a bar fight. So I don’t have any illusions about lack of abilities.

            A fit female pilot could operate the trim wheels without any problem. And an unfit male pilot might struggle with them. So gender is not really the issue.

      • @Rob

        Sometimes you don’t have a luck of having enough altitude to make roller-coaster, or posibity to untrim aircraft with the motor of stabilizer before switching it off. You are doomed.

        These are not a big changes but necessary for sake of safety. But no one wants bring them to the light… until next crash, which will be simply a death sentence for the MAX.

    • Keesje, the goal is both. MCAS should not have put the pilots in that position, But if they are placed there, it’s beneficial for them to be as able as possible to handle it.

      You continue to try to cast this as an either-or problem. It’s wrong to blame the pilots solely so the alternative is to blame Boeing solely. That’s irrational. Both contributed to the accidents, so it makes sense to address both.

      • Rob, for me the JATR report is at this stage leading. A group of international experts, with time, unhindered by double interests and outside (public, commercial) pressure.

        Although they, JATR, could only give recommendations, they weigh way more for me (and many others) than other reports, proposals and suggestions.


        They reported what many refuse(d) to see.

        • Keesje, I think we can all agree on the value of the JATR recommendations. JATR was charged with reviewing the MAX design and certification as they applied to the accidents, and they did a good job.

          Their work has been factored into the recertification process by Boeing, FAA and EASA. Every recommendation may not be implemented in terms of a change to the MAX, but they have all been considered. Some may appear in training.

          However, there were also pilot issues involved. This has been shown in every instance where pilots have been tested. So we’d be remiss not to consider that as well.

          • Rob:

            As a Boeing employee you clearly are biassed to try to spread the blame out as much as possible.

            You either are not aware of or are deliberately ignoring all the movement in the last 10 years in regards to pilot issues.

            The root cause was Boeing and MCAS. They even lied about the issue to the point that the next trigger even with awareness the crew was not able to handle it.

            Boeing is fully aware of the regs for pilots world wide.

            Having seen US pilots do some incredibly boneheaded stuff with a perfectly good working aircrat, it could just as well have been US pilots.

            You are trying to make the issue equal and they are not.

            Pilots have every right to have a sane working aircraft and these clearly did not due to Boeing.

            Any pilot can tell you that task saturation is an issue.

            When an aircraft is acting totally contrary to what you were trained for, then its on the aircraft mfg not the pilots.

            Prior to MAX and its MCAS, there was not a single 737 that crashed due to AOA issues, not one.

            Boeing degraded the safety system and then killed 347 people as a result of that, plane and simple. They own it.

          • Rob,

            I thinks that’s a very valid point, we’d be remiss not to consider the pilot issue. The pilots should never have been put in that position, but they were, and we need to learn from that.

            Boeing, the FAA, Airbus, and all of the other airframers use test pilots to evaluate their aircraft, what seems to have been missing is a check with a very average pilot cohort.

            As you said a post or three ago “random pilot testing in December showed too much variation in pilot responses”.

            This mystical 4 second response time was fine for a test pilot about to perform a test, knowing exactly what was about to happen, and having planned their response in advance. It’s less useful in the real world, hopefully the expectations will have been re-set.

          • TW, you can repeat this mantra as many times as you wish. No one has denied the role that Boeing and MCAS played, so you are preaching to the choir.

            But if recovery was possible in the accidents, and we can adjust pilot training to make that more likely, then we should. I believe this is being done in the new training.

            Further all the pilot testing has shown weaknesses and deficiencies. We can address those in training as well. Why would we not?

          • “As a Boeing employee you clearly are biassed to try to spread the blame out as much as possible.” I agree with @TransWorld. Boeing motto “blaim pilots” always alive, even in the smallest way, even unresonable, always blame.

          • Rob:

            You deliberately change the phrasing to indicate things I have not only not said but have stated differently. Another term for it is propaganda.

            Pilot training adjustments are on going. Before your awareness occurred, it had been ongoing seriously since AF447.

            Pilots can be no better than the training they receive, its not like they are allowed to just go play with a Simulator or a real aircraft like a fighter pilot.

            In this case, the pilots had NO trianing for MCAS. They did not know it existed. They were lied to, it was not a 737NG and it was ot a NG by two critial aspec.

            Further, Boeing said the response was the same as a run away trim motor.

            That too was a lie, a runaway trim motor does not act remotely like MCAS did.

            You then ask an average line pilot to sort out Boeing assassination attempt. There is nothing that causes confusion more than a system that is not doing what all your training has taught you it can act like.

            Line Pilots are not test pilots. You can add into Boeing crimes that they know this and their response (which was bogus) was based on test pilots not line pilots.

            The cause of this crash was MCAS. The PIC pilots had thousands of hours on 737 with no issues.

            Boeing tells the Airlines that the MAX is identical to NG. Boeing also knows that Indonesia and Ethiopia have pilot standards that are below US standards for the Co pilot.

            They sold them a B-26 telling them it was a Cessna 150.

    • Regarding the Turkish Airlines Flight 1951 crash mentioned by keesje:

      Many decades ago, before I decided aviation would be too expensive as a hobby for me, and my poor eyesight would prevent me from having a career as a pilot, I was a student pilot flying Cessna 150 trainer planes, which had no autopilots, no autothrottles, and no fancy computer displays. I never crashed or stalled my no auto-anything trainer plane, nor did any of the other student pilots or private pilots at my airfield during the year I was active as a student pilot. If we wanted to not stall and crash, we could not rely on the autothrottles or an autopilot to keep us from going too slow, because we had neither, we had to instead be alert enough about scanning the airspeed indicator and other instruments, noticing changes in the sight picture out the window (such as nose vs. horizon, or in instrument conditions artificial horizon), control feel, and engine and wind noise, to detect dangerous changes in airspeed before they killed us. If we wanted to pass our FAA Private Pilot Checkrides (less strict than Commercial or ATP check rides) we had to stay within plus 10 and minus 5 knots of recommended approach speed, without autothottles or an autopilot, since we had neither. I find it difficult to see the cause of an accident in which professional airline pilots failed to do things that I had to do as a rank amateur beginner student pilot if I wanted to stay alive, such as looking at the airspeed indicator often enough to know that they had dropped 40 knots below approach speed, and which would have gotten me flunked on a FAA private pilot checkride, to not be primarily pilot error. If they weren’t looking at the airspeed indicator because they were relying on the autothrotlles, then that suggests to me that safety might be improved by outlawing autothrottles, or at least requiring pilots on checkrides to fly all maneuvers with the autopilot and autothrottles off, to prove that they are capable of operating their aircraft safely based on scanning their flight instruments if the auto everything fails. Do those of you who have never flown a plane but do drive cars need to look at a computer or listen for a computer alarm to know if you are going way too fast or way too slow, or can you tell by looking out the window and listening to the engine and road noise if you are going way too fast or way too slow for conditions, such as 25 MPH on a freeway or 60 MPH on a residential street, or know by steering wheel feel if you are going too fast around a corner? Following is an excerpt from the Wikipedia article on the Turkish Airlines Flight 1951 crash at the link after the excerpt.

      “At 144 kt, the pilots manually increased thrust to sustain that speed,[39] but the autothrottle immediately returned the thrust lever to idle power because the first officer did not hold the throttle lever in position. The throttles remained at idle for about 100 seconds while the aircraft slowed to 83 knots (154 km/h), 40 knots (74 km/h) below reference speed as the aircraft descended below the required height to stay on the glideslope.[41] The stick-shaker activated at about 150 metres (490 ft) above the ground, indicating an imminent stall, the autothrottle advanced, and the captain attempted to apply full power.[41] The engines responded, but there was not enough altitude or forward airspeed to recover, and the aircraft hit the ground tail-first at 95 knots (176 km/h).[41]

      The data from the flight recorder also showed that the same altimeter problem had happened twice during the previous eight landings but that on both occasions the crew had taken the correct action by disengaging the autothrottle and manually increasing the thrust.”


      The autothrottle glitch definitely needs to be fixed, the autothrottles should reduce rather than increase workload, but if I could keep from stalling an airplane without autothrotlles as a rank amateur student pilot, it it OK for airline pilots to be dependent on proper function of the autothrottles or autopilot to keep from stalling because they do not look at their airspeed indicators often enough to notice a 4o knot decrease in airspeed over 100 seconds? My answer is that Turkish Airlines is on my no-fly list because they employed pilots who could not do things that I could do as a crappy rank amateur student pilot. If you want my airline ticket money, you need to have pilots who put to shame everything that I was able to do as a crappy beginner student pilot.

      • Regarding the following from the excerpt from the Wikipedia article on the Turkish Airlines Flight 1951 crash in my post above.

        “At 144 kt, the pilots manually increased thrust to sustain that speed,[39] but the autothrottle immediately returned the thrust lever to idle power because the first officer did not hold the throttle lever in position”

        I had this same bad habit of taking my hand off the throttle during takeoffs and landings. My Private Pilot flight instructor quickly cured me of this habit by yanking the throttle forward or back, whichever would cause more trouble, if I took my hand off the throttle during takeoff or landing.

        From Chapter 8. “Approaches and Landings” of the FAA “Airplane Flying Handbook” for Private Pilots.

        “It is recommended that a pilot form the habit of keeping one hand on the throttle throughout the approach and landing should a sudden and unexpected hazardous situation require an immediate application of power. ”


      • Did you read the full report? There was a single (point if failure) broken sensor and the emergency warning system was giving the pilots wrong and conflicting information while quietly pulling the throttles. Did your Cessna do the same?

        Boeing quietly corrected it later on, while denying responsibility, making sure unwelcome observations went under the table.

        So much under the table, that they claimed the emergency warning system never had any problems, during MAX certification.

        Turkish needed a lot of new aircraft and political support elsewhere and time did its thing.

        JATR should do a review of TK1951. All info is available. Boeing and FAA would strongly resist.

        The 737NG has an outdated emergency alert system and flight protection system & it was copied onto the MAX. To keep up with the NEO and save money for stock buy backs and dividents. And huge executive bonusses based on that.

        Responsible people were moved around & Muilenberg got his golden parachute. But have things changed really?

        • I think AP’s point was that the pilots relied on the automation more than was safe for the circumstances. JATR made this point as well, as has the NTSB numerous times, that automation can breed complacency.

          Automation always carries the risk of failure. Manufacturers should be responsible for those failures. But pilots should also be able to handle a failure in automation. That provides the greatest protection for passengers.

          As I recall from the accident report, the failed radar altimeter had provided false data numerus times before and was known to be flaky. Boeing had contacted the manufacturer to address the issues.

          The worst part was that the altimeter did not detect its own failure, as it was supposed to do, so it flagged the false reading as valid. Boeing eventually switched the altimeter model to one that was more reliable.

          • Calhoun suggests there now may be a wholesale shift coming, I agree:

            “We might have to start with the flight control philosophy before we actually get to the airplane. Because the decision around pilots flying airplanes, that’s a very important decision for the regulator and for us to get our head around,” he said. “As you well know, we have always favored airplanes that required more pilot flying than maybe our competitor did. We’re all going to have to get our head around exactly what we want out of that. That’ll be a process that will go on alongside of the next airplane development.”

            Boeings immediately pointing at pilot failure that we saw at TK1951, JT610, has become unacceptable. It became clear what happened, how retaining old system / processes became a goal in itself, while avoiding introducing widely available superior flight control and protection systems.

            Continuing using flawed reliability statistics, assumptions and old mantras on pilot in control increasingly looks weak instead of consistent.

            Picking out the pilot interface fragments out of the JATR report and twisting them (assuming nobody checks?) is bad pratise a far as I’m concerned. Maybe read out loud the JATR recommendation & please inhale.

            They are about design philosophy (Changed Product Rule) and the delegated certification process (DOA). Not about pilot needing better training. The HR recommendation (7) goes much further than pilot training, more about good cockpit design. Please stop suggesting it is about pilot training, it is not fair to the JATR and victims families.


          • Keesje, the JATR was charged with evaluating the MAX design and the certification review process, to provide recommendations to Boeing and FAA. They were not charged with examining the role of the pilots or airline.

            Yet they went out of their way to mention factors that impacted pilot actions, and assumptions of those made by Boeing and FAA. They also discussed the impact of automation on pilot responsiveness, as well as complacency and the erosion of skills. They would not have done that if this was exclusively a MAX problem.

            I welcome Calhoun’s statement, as we do absolutely need to consider the pilot-aircraft interface, and look for ways to improve.

            I think the conflict occurs when you insist that pilot performance and safety are entirely on Boeing. The reality is that there will always be failures, and we know that pilot responsiveness to failures is key to safety. It’s really a partnership of both that creates the system.

            Boeing has an obligation to protect pilots as much as possible by providing good automation and interface, but pilots have an obligation to be as prepared as possible for failures in that automation or interface that may occur.

            In the accidents, we saw both failures in the automation/interface, and failures in pilot responsiveness. The same type of pilot failure has also been repeatedly demonstrated in each round of pilot testing that has occurred.

            It takes improvement of both factors to make a truly safe system. To me, that seems so obvious as to be beyond question or debate. The most dangerous thing, in my view, is not to consider them both, but focus on one or the other in the interest of assigning blame, or defending reputation.

            Some have defended the pilots, some have defended Boeing, but in the end it’s the passengers that must be defended from failure, of all kinds and all sources.

            I don’t know how to say it any more clearly than that, so I’ll leave it there.

          • Rob:

            Pilots can no more affect their training that I can stop the sun from coming up tomorrow . One Sim session costs $15,000 an hour (yes I know this, I supported a Flight Simulator) . That is direct costs, it does not include Sim and bldg payoff or associated costs to the individual (vehicle, food, scheduling )

            Back in the day I could get 727 time, at 25,000 an hour.

            That training is set by the AHJ and Boeing has its thumb on the scale including saying that the MAX required no training.

            The pilots, unless they had a prior Military career per Sullenberg only get the training they are handed.

            To put this on the pilots is gross ignorance of how the system works.

          • TW, I’ve never suggested that pilots go it alone and train themselves. What I’ve suggested is that the training standards should be advanced to better include flying and recovery skills, so they are better prepared for unexpected events. That would be a function of the improving the entire training system.

            Boeing will have to pay for at least some of the training that is now required for the MAX. Airlines may pay some as well, or purchase simulators. All of that is to the good, and is consistent with my comments

          • Pilots paying for their training after getting commercial license?
            At Ryanair they do
            “Pilots wishing to join Ryanair will have to pay 5,000 euros ($6,200) for their so-called type rating course to fly the 737, down from 29,500 euros.
            A type rating determines which kind of planes pilots fly, often a 737 or an A320 at Europe’s low cost carriers, and is done after gaining an airline transport license.”

  20. So lets look at an example of a pure pilot screw up.

    PIA had an A320 (note that its an Airbus by the way Rob) on approach to (Islamabad I believe). They had the approach messed up, they dropped the gear and then retracted it, never put it down again, and landed on the engines.

    they then amazingly they got it back in the air and crashed as both damaged engines quit.

    That is purely pilot causes (you can blame the Pakistan AHJ for a system that lets people like that as pilots).

    While I have issues with Airbus and their so called automation, none of that was in play. Purely on pilots.

    Boeing on the other hand put a lethal system into the MAX that manifested itself at takeoff (the most critical part of the flight) and task overloaded the pilots who had good record. (with a new w system that Boeing had not told anyone was on the aircraft )

    And oh, by the way, that cutout switch, no, we changed that to and it does not do what you are trained that it will do. I would call that Russian Roulette with 4 cylinder loaded on a 5 cylinder revolver (one flight was saved by a jump pilot who had time to assess the issue and help the pilots) – notice that the 737 is normally only a two man cockpit?

    That is the stark and clear difference

    Boeing despite the NTSB telling them they needed to change how their auto throttle did not work the way it should, refused to do so. Only the FAA can make them and the FAA being in Boeing pocket will not.

    That is standard Boeing MO. They only do whats right when forced to, not because its the right thing to do.

    • TW, this is yet another appeal to the either-or argument. Note that an accident can have multiple causes, as the MAX accidents did, and as many accidents do.

      Reducing the problem to the level that allows you to make your argument, is not sufficient. The problem remains more complex, and the solutions must be as well. Hence the need to address all causes, and not just select the ones that uphold our world views.

      • Rob:

        That is simply that you have your view baked in and facts do not change it.

        The MAX crashes were purely do to Boeing and on Boeing.

        The pilo0ts were put in an impossible position and given a brand new lethal system to deal with.

        Safety should not be a crap shoot. That is what Boeing made it.

        Two out of 3 crews failed and only by the grace of a jump seat pilot was the other one avoided.

        Regardless of all other circumstantial, this would have occurred.

        Sullenburng weight in and called it garbage.

        What you are arguing is tens of thousand of safe flights occurred without MCAS and then two lethal flights occurred with few MAX in service and its the pilots?

        And you refuse to ackloowledte pilot training has been a serious on going issue since well before you joined in.

        The same exists for automation and its issues.

        You really should educate yourself first. You simply make yourself a Boeing fan with your argument.

        You should look up Bjorn assessment of this. Your argument is nothing more than a 1st grade student arguing with Einstein (Bjorn being Einstein in case you don’t get it)

        • TW, I’m sure you don’t remember, but I asked Bjorn about this in his Corner column assessment of JT610, November 26 2019.

          He agreed that the FO had made mistakes, and also had issues in his check records which helped explain them, but pointed out the FO behavior was consistent across JT043 and JT610. So he gave them the benefit of the doubt, as they were stressed in the moment. I agreed with that assessment, as did you at the time.

          As I’ve always said, it’s understandable that the pilots made those errors. But it’s also true that if there were errors, we can approach them in training to help improve for the future. My guess is the MCAS malfunction, or the similar runaway trim, will be emphasized in the new training.

          • The error were induced by task overload, which also made vastly worse by the fact that MCAS did not manifest the way Boeing said it did (Boeing lied)

            None of that would have occurred if not for MCAS. If you could have deleted MCAS from the program the aircraft would have been perfectly safe. Only current Boeing management culture could have turned a perfectly fine flying aircraft into something lethal.

            Boeing cannot change other countries piloting requirements (though I have listed many examples of US and European hose ups so its not exclusive to Asia, Africa etc)

            They can provide an aircraft that does not kill people (and they can take responsibly for their actions, not blame the pilots)

            Those errors were being addressed here and in Europe and the better ME and Asian Airlines.

            So, tell me, what are you going to do about Ethiopia and its fling rules? Or Indonesia where a pilot knows if he refuses a flight he will get fired?

            You give them a safe aircraft (PIA A320) and then when it crashes, the blame is solely on the Airline, the AJH, Country and not Boeing.

            Boeing gave them an aircraft that was demonstrably not safe.

            Bottom line is you refuse to acknowledge the pilot issues are on going and have been for a long time.

            They were not the primary cause of the crash. Its noted as the maint part, but primary cause was and is Boeing. Plane and simple.

            When 95+% of the cause was an lethal system on the MAX, then its not its a little of this and its a little of that.

          • TW, part of the renewed mandate and funding to the FAA is to work with foreign regulators to improve pilot standards and compliance. That is done for a reason, because no matter how safe the aircraft is, it can always be crashed by pilot error.

            So it makes sense to do this, as it also makes sense to acknowledge the pilots’ roles in the MAX accidents. The percentage blame argument is not a very good one. It’s playing the blame game that I cautioned you about earlier. I don’t care about that at all, I care about addressing any errors that occurred, so they don’t occur again.

            We can have understanding and sympathy for why the errors occurred, but the errors still have to be addressed, for the safety of others.

            If you and others here don’t agree, that’s fine. But there will be a greater emphasis on this going forward, and that’s entirely appropriate.

  21. “”For months, the slightest incident is going to garner headlines as a “blow to MAX,” or something similar. These will be unfair.””

    No, not with Boeing’s culture and their self-certification bullshit. Boeing kept/keeps lots of things secret and it’s not only the MAX, it’s everything Boeing did and still they didn’t change.
    It’s also not only Boeing, it’s the whole aviation system. Start with Obama/Trump who cut the spending. You have to imagine this, Trump grounded the MAX.

    • Trump kept it flying, it was China that grounded it followed by all other AHJ.

  22. This is a good brief of the flight and the post flight activities


    The heavy lifting is really before those flights when it was rung out by Boeing.

    FAA flying it is the Trust but We darned well need to verify it (this time)

    They will have the data from those flights, but they will also have Boeing data on its flights (which we hope they have not hidden or lost any part that is not golden)

    As I have noted before, once they corrected MCAS, I had no issues flying a MAX. Its going to be common on the Anchorage to Seattle run and once Covde is dealt with (hopefully by next spring) I have a number of visiting obligations.

    All the rest of the new MAX issues are just window dressing for me, the aircraft was fine. Cross linked computers vs stand alone that have worked forever, whatever.

    The concern with Boeing is that they just repeat the behaviour once the eye is off them.

    The removal of the lightening protection on the 787 without going through the legal process to do so, just tells you the upper management culture is still corrupt.

    The press has let that one slide but its the same as KC-46 issues that never end, FOD in the 737MAX tanks showing just how sloppy the culture has been allowed to become.

    At one time a Boeing aircraft was a source of pride, no longer and management does not care unless they get caught.

    • Why is the FAA hiding that the MAX-7 was tested.

      FAA Statements:
      “The FAA will review Boeing’s final design documentation in order to evaluate compliance with all FAA regulations.”
      “We will lift the grounding order only after we are satisfied that the aircraft meets certification standards.”

      Seems the FAA can’t certain express what they want to do.

      Boeing agreed that MCAS played a roll in the crashes.
      Many people say that JT610 and ET302 crashed because of MCAS.
      But even after MCAS activated, JT610 was still flying. It was possible for the Captain to fight MCAS again and again. He did that many times and JT610 was still flying. The problem was he got exhausted to pull the column. Then he let the FO fly and the FO was suprised about the forces and didn’t fight it. Only after that JT610 crashed.
      If the column forces were low JT610 would never have crashed.
      The accident report and JATR mentioned that the column forces don’t meet regulations.

      It seems the FAA don’t want to fix this, but is writing about compliance with all FAA regulations and certification standards.
      What is the intention to lie about safety?

      • Leon, perhaps Boeing wanted to complete certification of the MAX-7 with the same flights, if that was incomplete at the time of grounding.

        With regard to JT610, I think it would be more accurate to say that the captain had learned to interrupt and counteract MCAS with electric trim. Thus he only experienced high column forces for the first few activations. After that, he had it handled pretty well. He trimmed back to neutral column forces each time, as he is trained to do.

        In the meantime, the FO was having no luck finding a relevant reference in the QRH. This was not his fault as there was no mention of MCAS there. The closest thing was runaway stabilizer, but in neither JT043 nor JT610, did the FO identify that as the problem, as Boeing had assumed they would.

        So the captain, having attained the requested holding pattern at 5000 feet, traded roles with the FO so he could look in the QRH himself. The voice recorder picked up the sound of pages turning.

        The FO had not understood how the captain maintained control of MCAS, and the captain did not explain or instruct as control was transferred. So the FO did not trim to counteract MCAS as the captain had done. Thus the FO did experience high and increasing column forces for the entire remainder of the flight.

        As the FO was progressively losing the struggle for control, he alerted the captain that the aircraft was losing altitude. The captain responded “it’s ok” just before the crash. That would indicate the captain’s focus was on the QRH. It appeared the captain had grabbed the column at the end. At that point, the forces had far exceeded the FAA limits.

        None of this makes the tragedy any less. And we can understand their situation and how mistakes were not only possible, but made much more likely by MCAS. But there are lessons to be learned from them, if we are willing to look.

        • “”With regard to JT610, I think it would be more accurate to say that the captain had learned to interrupt and counteract MCAS with electric trim. Thus he only experienced high column forces for the first few activations.””

          From Bjorn’s Corner:
          “As the Captain, who was flying, compensated MCAS nose-down trim with a nose up manual trim, MCAS reset and trimmed nose down again after a five-second wait. This repeated 22 times before the Captain asked the First Officer (FO) to take over the controls.”

          The Captian fighted MCAS 22 times by pulling the column with his arms.
          The crash report and JATR mentioned that the forces don’t follow regulations.
          Did Boeing self-certified the forces on the MAX?
          Are the forces still not following regulations on the MAX today?
          How about the forces on the NG?

          • No, the JT610 captain used the electric trim buttons to bring the column forces back to neutral, after the first few MCAS activations. This is shown clearly in the released accident data, and is consistent with Bjorn’s statements. I actually asked Bjorn about this in the November 29th Corner, and he agreed.

            The captain had mastered the MCAS cycle and continued his climb to 5000 feet, before turning over control to the FO. The aircraft was stable at that point, but it required a finger press on the control column ANU button every 5 to 15 seconds, to interrupt and reverse MCAS.

            My guess, although again pure speculation, is that the captain assumed the FO had observed his solution and would continue it, when he handed over control. But in fact the FO had been absorbed in the QRH, and had not realized what the captain was doing to keep things stable. The finger press would not be obvious to an observer, especially with the captain’s stick shaker active.

            Then without that knowledge, the FO was not as experienced or skilled as the captain, so he wasn’t able to deduce how to control MCAS with electric trim, as the captain had.

            This aspect was noted in the accident report, as an issue with CRM. The captain had notes in his pilot check file about not communicating with the pilot monitoring, and preferring to do things himself. The FO had notes in his checks about reduced manual flying skills.

            It may have been a case of the FO being deferential to the captain as well. That has been a factor in many accidents. The FO only alerted the captain once as he was losing control.

            So given the crisis they faced, this was an unfortunate combination of behaviors. But it affirms the Swiss cheese model, where accidents happen because vulnerabilities happen to align.

          • If Bjorn made a mistake in his corner, he would have corrected his text in his corner, like he always do, because many people only read the corner, not the comment section.

            And I’m also sure that the captian and FO only pulled the column.

            At that time of JT610 MCAS wasn’t known, both pilots were fighting a ghost.

            JT610 crashed because of these high forces!
            Do you think both pilots would fly into the ground if they could pull the column with a finger?
            Would you want to die if you can prevent it easily with a finger?

          • Leon, Bjorn did not make a mistake in his column, you are making a mistake in interpreting it, as well as other data. That has been consistently true.

      • Leon,

        I think you are conflating two separate issues here. They are related issues, but indeed separate. The first issue is the sudden change in column force at high AoA near stall that MCAS was intended to correct. This is the issue that the reports refer to in bringing to light the processes that led to a poorly designed MCAS. The column force on the MAX did not progress smoothly enough with increasing AoA near stall to meet the regulations, but the magnitude was always very manageable. In fact, MCAS was needed because the column force suddenly became too light at high AoA. So, if properly flown and not malfunctioning, the column force required to fly the MAX are well within standards.

        The second issue is the fatally high column forces experienced by the pilots in both crashes caused by a severely out of trim stabilizer. The cause of this severe mistrim was a damaged/miscalibrated AoA sensor acting through a poorly designed part of the flight control system, MCAS. The column forces experienced by the pilots were indeed unacceptably high, but this was not by design. The flight control system was broken. In the first crash it was a grossly miscalibrated AoA sensor, and in the second crash the AoA sensor was completely damaged by a suspected bird strike.

        So, the crashes didn’t happen because Boeing designed the column forces to be too high. The crashes happened because MCAS responded badly to bad input from broken sensors.

        • Yes, thank you Mike. Although Leon will not accept this, it’s a clear and lucid explanation.

        • Boeing PR at the end haha.

          You know there is a feel system, a second feel system is not needed.

          The reports mentioned too high column forces. Boeing didn’t follow the regulation.

          JT043 was fighting MCAS too and they didn’t crash. But if they had same high column forces they would have crashed too.

        • “”The column force on the MAX did not progress smoothly enough with increasing AoA near stall to meet the regulations””

          Do you mean after 15 months grounded the MAX still doesn’t meet regulations?
          If the MAX doesn’t meet regulations it can’t be certified!

          • The MAX meets certification regulations with MCAS. It always did. That’s why MCAS was added.

          • “The MAX meets certification regulations with MCAS.”

            But much more weight has that other _essential certification requirements_ fell by the wayside
            due to MCAS specific design decisions.

    • “The FAA will review Boeing’s final design documentation in order to evaluate compliance with all FAA regulations.”

      The FAA knew close to nothing about MCAS, only after JT610 the FAA looked closer into MCAS and were surprised.
      MCAS is using stabilizers, JATR called that “novel”.
      If there is no certification standard for this “novel” solution there can’t be compliance with FAA regulations.
      Why is the FAA fooling the flying public with safety issues?
      Of course this doesn’t matter for the FAA, the flying public should enter the MAX and die, same as the passengers of ET302. When ET302 crashed the FAA had enough time to evaluate MCAS but did nothing.

      • After JT610, the FAA issued an AD alerting pilots to the repetitive nose-down actions associated with the MCAS failure in JT610, and the correct procedures to handle it. It was required material for pilots and was a mandatory addition to all MAX QRH.

        They also directed Boeing to resolve the MCAS issues within 6 months. Boeing had set a resolution date beginning in April, with updates to be completed by June. It was thought at the time, that this would be sufficient to avoid another accident.

        That turned out to be wrong, and resulted in the second tragedy of ET302. I’m sure their decisions would have been different if they thought it could happen again so quickly, and that the AD would be ineffective in preventing another occurrence. Neither of those were expected.

        We don’t know why the captain of ET302 did not trim back to neutral as the captains of JT043 and JT610 had done, and probably never will know. But since the FO of JT610 also did not, there is a precedent for those actions.

        As to the overspeed condition, the ET302 interim report is investigating the effect of the airspeed unreliable alert on the auto-throttle. Like MCAS, the auto-throttle used the left-side instruments. In the event of the unreliable airspeed, the auto-throttle does not throttle back automatically with airspeed. It maintains takeoff thrust and leaves it to the pilot’s judgement to reduce thrust.

        We know that the captains of JT043 and JT610 did manage their throttle, although they too were late in doing so, with higher than normal airspeed.

        But we also know the ET302 pilots were focused on the MCAS malfunction and the QRH, and may not have been monitoring airspeed or throttle. So that became a contributing factor, even though the pilots did successfully run the QRH checklist to disable MCAS, as required by the AD.

        The final step of reactivating MCAS has been criticized, but was understandable given their circumstances, and the lack of awareness of airspeed, which would have suggested another solution. But again, even with electric trim becoming available, the captain did not trim sufficiently against MCAS.

        My own guess, although pure speculation, is that in the confusion, the captain had expected column forces to be neutralized at 2.4 units of stabilizer, when the correct value was about 4.6 units. He stopped trimming at 2.4 units each time he used electric trim. Again we don’t know why, as that would still be a significant mis-trim with high column forces. But it was another contributing factor.

        In the end it’s a total & completely unnecessary tragedy. In hindsight we can see many key choices that would have avoided it, by every party involved. Yet each party did what they thought was best at the time. No party acted out of malicious intent or the desire for loss of life.

        It’s an example of how good intentions alone are not enough, and how multiple levels of safeguards can still result in failure. This has been described as the Swiss cheese effect, with holes & flaws & vulnerabilities lining up, and that is an apt description. It’s shocking that it could happen twice, so I understand the public anger and upset that accompanies it, especially that directed at Boeing and FAA.

        • “”After JT610, the FAA issued an AD alerting pilots to the repetitive nose-down actions associated with the MCAS failure in JT610, and the correct procedures to handle it. It was required material for pilots and was a mandatory addition to all MAX QRH.””

          The AD was a 99% copy of Boeing’s bulletin, because the FAA knew nearly nothing about MCAS. And with the knowledge we have now Boeing’s bulletin was completely crap.

          “”They also directed Boeing to resolve the MCAS issues within 6 months. It was thought at the time, that this would be sufficient to avoid another accident.””

          In December the FAA calculated that 15 more crashes will happen, in DECEMBER. Lets talk about killings and crimes.

          • Yes, 15 more accidents over the 30 year lifespan of the MAX fleet of 4,800 aircraft, if no corrective action was taken (no AD and no MCAS fix). That made the statistical probability small that an accident would occur in a fleet 10 times smaller within 6 months.

            But since the initiating event (AoA failure) was random, a statistically improbable occurrence could actually occur at any time, as we found out. And the AD did not have the deterrent effect that was expected.

            The AD did prevent the errors that occurred in JT610, but new errors occurred in ET302, with the same result because the underlying MCAS problem was the same.

            As Pablo said when Steve asked why it happened twice in a 3rd world country, the second AoA failure was bad luck.

            The first AoA failure was due to improper operation & maintenance, so was not statistically random or the result of luck.

          • I even question only 15 accidents.

            Boeing made a caculation of AoA failures. They came up with 20 failures within 17 years. IIRC this is measured in failures per flight hour.
            If a true calculation is made for ET302, JT610, JT043 and another Lion Air flight before that it will deliver a high result for only these 4 flights and would bring Boeings faked calculation of 17 failures within 20 years down.
            IIRC JT043 alone had 3 failures within 3 flight hours. It can’t be counted as only one failure and on the other side counted with 3 flight hours for this single flight.

            At that time in early December many people tried to find out how the FAA came up with 15 accidents and these people calculated a much higher rate.

            It only needs to be checked how many flight hours both crashed planes had, both were below 500 flight hours.

            But the FAA did NOTHING.

          • Leon, we’ve discussed the statistical methods in detail in earlier threads, when that news first broke. The FAA used the accepted model and their calculations were subsequently checked by others, and found to be correct. This is also mentioned in the IG report.

            Other models have been proposed that provide much higher estimates, but they are not supported by the history of the 737 as highlighted by Peter Lemme.

            They assume a sample size of only the MAX in service, and count JT043 and JT610 as multiple failures of the same sensor.

            But there is no basis for the notion that the MAX is more susceptible to AoA failure than other 737 models. And the JT043/JT610 sensor failed only once, it just wasn’t found over several days and opportunities.

            You can shift the bases around in statistics to get higher or lower numbers. The FAA model is used around the world and is considered valid. It was their best estimate. They cannot foresee the future.

            As I mentioned, in a statistical probability of random causes, the prediction is an expected rate over time, but the random cause can occur at any time. So a risk of that is always present, it’s just very low. But it’s not zero.

      • The FAA should have read the JATR report and should have UNDERSTOOD the report after 9 months. MCAS is using stabilizers, JATR called that “novel”. The FAA should have thought about this novelty already and if the FAA is interested to be in harmony with other regulators, talked with other regulators about this novelty. If there is no certification standard for this “novel” solution there can’t be compliance with FAA regulations.

        So how can the FAA print this statement now:
        “We will lift the grounding order only after we are satisfied that the aircraft meets certification standards.”

        Why is the FAA fooling the flying public with safety issues?

        • Leon, people in this thread have gone far out of their way to help you understand the issues, but you refuse to accept the established facts or logical reasoning.

          So I think there is nothing more to be said or done. You aren’t going to change your views, and that’s fine. Like others here, you don’t have to fly the MAX if you think it’s unsafe.

          But it will return to service and most people will consider it as safe as other 737 models have been. That will be the final result.

        • “MCAS is using stabilizers, JATR called that “novel”.”

          MCAS made the elevators and control column useless.
          If the elevators can’t be used, the pilot needs ways to steer the plane.
          The MAX need to be designed so that the pilot can steer with stabilizers.
          Boeing said in the bulletin that the stab trim needs to be cut off. The only way to steer the plane then is by using the manual trim wheels. The trim wheels were never designed to only steer the plane, beside that they were made even smaller which increased the forces.
          On ET302 the FO couldn’t move the trim wheel, but he learnt on the sim how to use the trim wheel.

          The only way to steer the MAX are the trim wheels which sometimes can’t be moved, and it seems the FAA thinks this meets certification standards.
          JT043 flights are now the new standard. FAA can’t be serious.

          • In ET302, the trim wheels couldn’t be moved because the aircraft exceeded the maximum safe operating speed, and the aircraft was severely out of trim. The simulators were not programmed for those conditions, but they were correct for the expected flight operating conditions.

            That has since been rectified, the simulators are now programmed to be accurate in all flight conditions.

            Pilots are trained to trim the aircraft to neutral column forces using electric trim, if it’s working. It was working in all the flights. Trimming to neutral would have both prevented the accidents and allowed the manual trim wheels to be operable. Also controlling airspeed to within safe limits.

          • Speed is often unreliable.
            JT043 flights are now the new standard. People on that flight got traumas.
            MCAS can still reset if both sensors have 5 degrees difference.

            This can’t be the result of a “novel” solution. Instead of getting better it got worse.
            JT043 might happen again, then people will see what the FAA did.
            JT043 was a new plane with less than 1000 flight hours. An aged jackscrew might act different.
            Flight attendents might know this already. Will they fly.

          • Leon, you’re just making things up now. No response is possible or needed. The MAX will be certified and that is the appropriate outcome, whatever you may think or say.

          • Who certified the jackscrew? Was it Boeing?
            Was it in the 1980s? And after that it was never checked again?

            Every right mind with knowledge would think:
            “Why would EASA and Canada certify this?
            They are not doing a safety job.
            Are they the mafia?
            Is Boeing paying them?”

  23. A very political & important statement by FAA. Addressing international concerns, a resistance to rushing. But also some question marks, e.g. who will release for service aircraft build prior to the grounding?

    • Keesje, I had thought the FAA would do that too, but apparently not. Boeing cannot. So it would have to be the airline maintainers, they have the power to certify compliance with all AD’s, after which the pre-existing airworthiness certificate is resumed. However after this long on the ground, there may be additional inspections and compliance tasks required.

      John Goglia has a podcast that discusses what goes wrong with a grounded aircraft and what must be done to restore it. He said it’s likely the airlines have been regularly starting the engines and exercising the systems. In some cases they may have permission for brief non-commercial flights, moving the aircraft around. The cost of that is included in claims of compensation against Boeing.

      I’m sure that Boeing and the FAA will provide RTS guidance and assistance.

  24. If I read the self convincing, consistent generalizations, deflections, spreading of doubts, avoiding responsibility on the topic, I worry if Boeing is learning.

    Having witnessed this for a long time, it makes me worry about it’s future.

    Putting militairy guys in charge of public communication tells a lot.

  25. To calculate how often an AoA sensor fails, Boeing checked how often the stickshaker activated. The NTSB said it was 27 times in 17 years. Boeing made 20 times in 17 years out of it.

    But to count only stickshaker activations is not really good to get real numbers of wrong signal events.
    The 2 flights before JT043, the stickshaker didn’t activate but a failure was logged into the computer. That’s why the AoA sensor was changed.
    There might be 500 logged AoA failures in 17 years, but Boeing calculated with 20.

    Not really a surprise. That must be standard Boeing practice.
    The NTSB didn’t question this too … why?

    • Leon, Boeing counted those instances of AoA failure that resulted in stick-shaker activation, because those instances also would have triggered MCAS, had it been present.

      They also removed instances of the same sensor failing that occurred on multiple flights.

      Not every AoA failure is severe enough to activate stick-shaker. As you mentioned, the failure of the original Lion Air AoA sensor was minor and logged in the computer without causing an upset in flight. It would have been better to leave that sensor in place than to replace it with a defective sensor, as was done.

      Boeing did the search properly, it was also replicated by Peter Lemme in his research, and was quoted in the JT610 accident report. I’m sure they would have made some effort to confirm before publishing. The NTSB also would have checked.

      • “”the failure of the original Lion Air AoA sensor was minor and logged in the computer without causing an upset in flight””

        How can you say it was minor, there were system warnings, so pilots got unreliable data.

        MCAS2.0 accepts a 5.5 degree difference of both AoA sensors. If one AoA sensor is already wrong it could add to the difference. If the other AoA sensor fails too MCAS could activate in level flight.

        Stickshaker activations can’t be used for calculations for MCAS2.0 how often AoA signal failures happen.

        “”They also removed instances of the same sensor failing that occurred on multiple flights””

        AoA sensor signals not only fail because of bird strikes or ramp hits. Signals can fail because of a bad wire connections, eroded vanes causing erroneous data, computed failures and maintenance mistakes.
        Bird strikes and ramp hits can easily be seen. Bad connections and eroded vanes are not easy to detect and the JT610 report shows that engineers have trouble to fix the problem.

        If maint can’t fix the problem it’s a serious issue and should not be removed from the calculation.
        There might be thousands of maint mistakes in 17 years, but Boening is only counting bird strikes and ramp hits.

        If there are only 20 AoA failures in 17 years worldwide there is no need to keep spare sensors stored. They have spare sensors because failures happen often.

        • Leon, the earlier Lion Air AoA failure was as you described, intermittent readings that did not cause a flight issue. So it was flagged for maintenance and was replaced.

          Stick-shaker activations are a reliable indicator for a probable MCAS trigger. Lesser AoA failures would not trigger MCAS.

          MCAS now has sanity checking so even if two sensors were to fail in flight, it would not accept the erroneous inputs. Also AoA sensor readings are now displayed in the cockpit for pilots. Also MCAS can no longer exceed the pilot’s authority, even if it is falsely triggered.

          The JT610 report shows that maintenance did not test the new AoA sensor and falsified the records to show they had. Then provided investigators with false evidence of testing of another aircraft. They lied repeatedly. So it was absolutely not an issue of maintenance not being able to repair, or a mistake.

          • Thanks God investigators of Ethipian flight did not conside maint lied !! so aircraft xere IMMEDIATLY grounded … FAA was 3 days late but good chinese engineers made very quickly the right decision … even before Boeing who knew the problem for month before!!
            after almost 18 month I am not prepared to travel on a MAX

  26. According to the 8-31-20 Skies Magazine article at the link below, Transport Canada completed their 737 MAX re-certification test flights on 8-31-20 and used a 737 MAX 7 for all test flights. I don’t remember seeing this reported on in this blog. It is certainly possible that it was reported on in a post that I missed or only partially read. Below is an excerpt from the article.

    “On Aug. 26 and 27, crews moved into the Max 7 test aircraft, performing a series of evaluation flights in U.S. airspace. According to Transport Canada, that is the same aircraft used to conduct testing by the U.S. Federal Aviation Administration earlier in August.

    “The Max 7, 8 and 9 all have the same underlying flight control architecture,” wrote Transport Canada spokesperson Sau Sau Liu in an email to Skies. “In other words, the three variants are very similar and use the same control systems that needed to be assessed as part of the test flights. This is why the Max 7 test aircraft adequately supported the evaluation test flights.”


    • @AP: There wasn’t a report on Transport Canada on LNA. I’ve got a hospice situation going on in my family and my attention here is limited. EASA announced today it’s completed its testing.

      • Scott – I wish you and your family all the strength you need to get through your present trials, and happier times in the future.

  27. According to the following excerpt from the 9-11-20 EASA press release at the link after the excerpt, EASA has completed their 737 MAX re-certification test flights and the JOEB will meet next week in London.

    “The European Union Aviation Safety Agency (EASA) has now completed its test flights of the Boeing 737 MAX. These took place in Vancouver, Canada due to COVID-19 travel restrictions.

    As the next step in its evaluation of the aircraft for return to service, EASA is now analysing the data and other information gathered during the flights in preparation for the Joint Operations Evaluation Board (JOEB). The JOEB is scheduled to start next week in London, Gatwick in the United Kingdom.”


      • AP_Robert, Thank you for the links to the test flights. It would be interesting to know, if Canada or Europe will want to see a 737-MAX fly ‘naked’ sans MCAS. It sounds like they all want to test and analyze the results separately, and then come together to compare the results in a larger group setting. I hope they require the cutoff switches to the one trim motor to be rewired back to the classic/NG configuration. Then you could truly isolate the autopilot systems from the stabilizer while maintaining manual control. I’m not sure if the Speed Trim System can be turned off on the classic/NG 737’s? Of course there is one method of turning off STS and MCAS currently (the following short video is humorous, but, very true. It will turn off MCAS and STS, giving the pilot manual control)
        MCAS does hide well within the STS. You really can’t tell which is operating the trim. I don’t know if that’s changed now.

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